Directory [tphols-2011] is added to host the commented version of [Myhill.thy]. Directory [pres] is created to host a build session for logical image [ListP] which is essentially [Main] extended with [List_prefix.thy].
--- a/IsaMakefile Fri Jan 07 14:25:23 2011 +0000
+++ b/IsaMakefile Mon Jan 24 11:29:55 2011 +0000
@@ -19,7 +19,7 @@
session1: Slides/ROOT.ML \
Slides/document/root* \
Slides/Slides.thy
- @$(USEDIR) -D generated -f ROOT.ML HOL Slides
+ @$(USEDIR) -D generated -f ROOT.ML ListP tphols-2011
slides: session1
rm -f Slides/generated/*.aux # otherwise latex will fall over
@@ -29,19 +29,19 @@
## Paper
-session2: Paper/ROOT.ML \
- Paper/document/root* \
- Paper/Paper.thy
- @$(USEDIR) -D generated -f ROOT.ML HOL Paper
+session2: tphols-2011/ROOT.ML \
+ tphols-2011/document/root* \
+ ../*.thy
+ @$(USEDIR) -D generated -f ROOT.ML ListP tphols-2011
paper: session2
- rm -f Paper/generated/*.aux # otherwise latex will fall over
- cd Paper/generated ; $(ISABELLE_TOOL) latex -o pdf root.tex
- cp Paper/generated/root.pdf Paper/paper.pdf
+ rm -f tphols-2011/generated/*.aux # otherwise latex will fall over
+ cd tphols-2011/generated ; $(ISABELLE_TOOL) latex -o pdf root.tex
+ cp tphols-2011/generated/root.pdf tphols-2011/myhill.pdf
## clean
clean:
rm -rf Slides/generated/*
- rm -rf Paper/generated/*
+ rm -rf tphols-2011/generated/*
--- a/Myhill.thy Fri Jan 07 14:25:23 2011 +0000
+++ b/Myhill.thy Mon Jan 24 11:29:55 2011 +0000
@@ -1,12 +1,15 @@
-theory MyhillNerode
- imports "Main" "List_Prefix"
+theory Myhill
+ imports Main List_Prefix
begin
-text {* sequential composition of languages *}
+section {* Preliminary definitions *}
+
+text {* Sequential composition of two languages @{text "L1"} and @{text "L2"} *}
definition Seq :: "string set \<Rightarrow> string set \<Rightarrow> string set" ("_ ;; _" [100,100] 100)
where
"L1 ;; L2 = {s1 @ s2 | s1 s2. s1 \<in> L1 \<and> s2 \<in> L2}"
+text {* Transitive closure of language @{text "L"}. *}
inductive_set
Star :: "string set \<Rightarrow> string set" ("_\<star>" [101] 102)
for L :: "string set"
@@ -14,6 +17,8 @@
start[intro]: "[] \<in> L\<star>"
| step[intro]: "\<lbrakk>s1 \<in> L; s2 \<in> L\<star>\<rbrakk> \<Longrightarrow> s1@s2 \<in> L\<star>"
+text {* Some properties of operator @{text ";;"}.*}
+
lemma seq_union_distrib:
"(A \<union> B) ;; C = (A ;; C) \<union> (B ;; C)"
by (auto simp:Seq_def)
@@ -28,23 +33,92 @@
apply blast
by (metis append_assoc)
+lemma star_intro1[rule_format]: "x \<in> lang\<star> \<Longrightarrow> \<forall> y. y \<in> lang\<star> \<longrightarrow> x @ y \<in> lang\<star>"
+by (erule Star.induct, auto)
+
+lemma star_intro2: "y \<in> lang \<Longrightarrow> y \<in> lang\<star>"
+by (drule step[of y lang "[]"], auto simp:start)
+
+lemma star_intro3[rule_format]:
+ "x \<in> lang\<star> \<Longrightarrow> \<forall>y . y \<in> lang \<longrightarrow> x @ y \<in> lang\<star>"
+by (erule Star.induct, auto intro:star_intro2)
+
+lemma star_decom:
+ "\<lbrakk>x \<in> lang\<star>; x \<noteq> []\<rbrakk> \<Longrightarrow>(\<exists> a b. x = a @ b \<and> a \<noteq> [] \<and> a \<in> lang \<and> b \<in> lang\<star>)"
+by (induct x rule: Star.induct, simp, blast)
+
+lemma star_decom':
+ "\<lbrakk>x \<in> lang\<star>; x \<noteq> []\<rbrakk> \<Longrightarrow> \<exists>a b. x = a @ b \<and> a \<in> lang\<star> \<and> b \<in> lang"
+apply (induct x rule:Star.induct, simp)
+apply (case_tac "s2 = []")
+apply (rule_tac x = "[]" in exI, rule_tac x = s1 in exI, simp add:start)
+apply (simp, (erule exE| erule conjE)+)
+by (rule_tac x = "s1 @ a" in exI, rule_tac x = b in exI, simp add:step)
+
+text {* Ardens lemma expressed at the level of language, rather than the level of regular expression. *}
+
theorem ardens_revised:
assumes nemp: "[] \<notin> A"
shows "(X = X ;; A \<union> B) \<longleftrightarrow> (X = B ;; A\<star>)"
proof
assume eq: "X = B ;; A\<star>"
- have "A\<star> = {[]} \<union> A\<star> ;; A" sorry
- then have "B ;; A\<star> = B ;; ({[]} \<union> A\<star> ;; A)" unfolding Seq_def by simp
- also have "\<dots> = B \<union> B ;; (A\<star> ;; A)" unfolding Seq_def by auto
- also have "\<dots> = B \<union> (B ;; A\<star>) ;; A" unfolding Seq_def
- by (auto) (metis append_assoc)+
- finally show "X = X ;; A \<union> B" using eq by auto
+ have "A\<star> = {[]} \<union> A\<star> ;; A"
+ by (auto simp:Seq_def star_intro3 star_decom')
+ then have "B ;; A\<star> = B ;; ({[]} \<union> A\<star> ;; A)"
+ unfolding Seq_def by simp
+ also have "\<dots> = B \<union> B ;; (A\<star> ;; A)"
+ unfolding Seq_def by auto
+ also have "\<dots> = B \<union> (B ;; A\<star>) ;; A"
+ by (simp only:seq_assoc)
+ finally show "X = X ;; A \<union> B"
+ using eq by blast
next
- assume "X = X ;; A \<union> B"
- then have "B \<subseteq> X" "X ;; A \<subseteq> X" by auto
- thus "X = B ;; A\<star>" sorry
+ assume eq': "X = X ;; A \<union> B"
+ hence c1': "\<And> x. x \<in> B \<Longrightarrow> x \<in> X"
+ and c2': "\<And> x y. \<lbrakk>x \<in> X; y \<in> A\<rbrakk> \<Longrightarrow> x @ y \<in> X"
+ using Seq_def by auto
+ show "X = B ;; A\<star>"
+ proof
+ show "B ;; A\<star> \<subseteq> X"
+ proof-
+ { fix x y
+ have "\<lbrakk>y \<in> A\<star>; x \<in> X\<rbrakk> \<Longrightarrow> x @ y \<in> X "
+ apply (induct arbitrary:x rule:Star.induct, simp)
+ by (auto simp only:append_assoc[THEN sym] dest:c2')
+ } thus ?thesis using c1' by (auto simp:Seq_def)
+ qed
+ next
+ show "X \<subseteq> B ;; A\<star>"
+ proof-
+ { fix x
+ have "x \<in> X \<Longrightarrow> x \<in> B ;; A\<star>"
+ proof (induct x taking:length rule:measure_induct)
+ fix z
+ assume hyps:
+ "\<forall>y. length y < length z \<longrightarrow> y \<in> X \<longrightarrow> y \<in> B ;; A\<star>"
+ and z_in: "z \<in> X"
+ show "z \<in> B ;; A\<star>"
+ proof (cases "z \<in> B")
+ case True thus ?thesis by (auto simp:Seq_def start)
+ next
+ case False hence "z \<in> X ;; A" using eq' z_in by auto
+ then obtain za zb where za_in: "za \<in> X"
+ and zab: "z = za @ zb \<and> zb \<in> A" and zbne: "zb \<noteq> []"
+ using nemp unfolding Seq_def by blast
+ from zbne zab have "length za < length z" by auto
+ with za_in hyps have "za \<in> B ;; A\<star>" by blast
+ hence "za @ zb \<in> B ;; A\<star>" using zab
+ by (clarsimp simp:Seq_def, blast dest:star_intro3)
+ thus ?thesis using zab by simp
+ qed
+ qed
+ } thus ?thesis by blast
+ qed
+ qed
qed
+
+text {* The syntax of regular expressions is defined by the datatype @{text "rexp"}. *}
datatype rexp =
NULL
| EMPTY
@@ -53,11 +127,20 @@
| ALT rexp rexp
| STAR rexp
+
+text {*
+ The following @{text "L"} is an overloaded operator, where @{text "L(x)"} evaluates to
+ the language represented by the syntactic object @{text "x"}.
+*}
consts L:: "'a \<Rightarrow> string set"
+
+text {*
+ The @{text "L(rexp)"} for regular expression @{text "rexp"} is defined by the
+ following overloading function @{text "L_rexp"}.
+*}
overloading L_rexp \<equiv> "L:: rexp \<Rightarrow> string set"
begin
-
fun
L_rexp :: "rexp \<Rightarrow> string set"
where
@@ -69,157 +152,258 @@
| "L_rexp (STAR r) = (L_rexp r)\<star>"
end
+text {*
+ To obtain equational system out of finite set of equivalent classes, a fold operation
+ on finite set @{text "folds"} is defined. The use of @{text "SOME"} makes @{text "fold"}
+ more robust than the @{text "fold"} in Isabelle library. The expression @{text "folds f"}
+ makes sense when @{text "f"} is not @{text "associative"} and @{text "commutitive"},
+ while @{text "fold f"} does not.
+*}
+
definition
folds :: "('a \<Rightarrow> 'b \<Rightarrow> 'b) \<Rightarrow> 'b \<Rightarrow> 'a set \<Rightarrow> 'b"
where
"folds f z S \<equiv> SOME x. fold_graph f z S x"
+text {*
+ The following lemma assures that the arbitrary choice made by the @{text "SOME"} in @{text "folds"}
+ does not affect the @{text "L"}-value of the resultant regular expression.
+ *}
lemma folds_alt_simp [simp]:
"finite rs \<Longrightarrow> L (folds ALT NULL rs) = \<Union> (L ` rs)"
apply (rule set_ext, simp add:folds_def)
apply (rule someI2_ex, erule finite_imp_fold_graph)
by (erule fold_graph.induct, auto)
+(* Just a technical lemma. *)
lemma [simp]:
shows "(x, y) \<in> {(x, y). P x y} \<longleftrightarrow> P x y"
by simp
-definition
- str_eq ("_ \<approx>_ _")
-where
- "x \<approx>Lang y \<equiv> (\<forall>z. x @ z \<in> Lang \<longleftrightarrow> y @ z \<in> Lang)"
+text {*
+ @{text "\<approx>L"} is an equivalent class defined by language @{text "Lang"}.
+*}
definition
str_eq_rel ("\<approx>_")
where
- "\<approx>Lang \<equiv> {(x, y). x \<approx>Lang y}"
+ "\<approx>Lang \<equiv> {(x, y). (\<forall>z. x @ z \<in> Lang \<longleftrightarrow> y @ z \<in> Lang)}"
+
+text {*
+ Among equivlant clases of @{text "\<approx>Lang"}, the set @{text "finals(Lang)"} singles out
+ those which contains strings from @{text "Lang"}.
+*}
-definition
- final :: "string set \<Rightarrow> string set \<Rightarrow> bool"
-where
- "final X Lang \<equiv> (X \<in> UNIV // \<approx>Lang) \<and> (\<forall>s \<in> X. s \<in> Lang)"
+definition
+ "finals Lang \<equiv> {\<approx>Lang `` {x} | x . x \<in> Lang}"
+text {*
+ The following lemma show the relationshipt between @{text "finals(Lang)"} and @{text "Lang"}.
+*}
lemma lang_is_union_of_finals:
- "Lang = \<Union> {X. final X Lang}"
+ "Lang = \<Union> finals(Lang)"
proof
- show "Lang \<subseteq> \<Union> {X. final X Lang}"
+ show "Lang \<subseteq> \<Union> (finals Lang)"
proof
fix x
assume "x \<in> Lang"
- thus "x \<in> \<Union> {X. final X Lang}"
- apply (simp, rule_tac x = "(\<approx>Lang) `` {x}" in exI)
- apply (auto simp:final_def quotient_def Image_def str_eq_rel_def str_eq_def)
- by (drule_tac x = "[]" in spec, simp)
+ thus "x \<in> \<Union> (finals Lang)"
+ apply (simp add:finals_def, rule_tac x = "(\<approx>Lang) `` {x}" in exI)
+ by (auto simp:Image_def str_eq_rel_def)
qed
next
- show "\<Union>{X. final X Lang} \<subseteq> Lang"
- by (auto simp:final_def)
+ show "\<Union> (finals Lang) \<subseteq> Lang"
+ apply (clarsimp simp:finals_def str_eq_rel_def)
+ by (drule_tac x = "[]" in spec, auto)
qed
-section {* finite \<Rightarrow> regular *}
+section {* Direction @{text "finite partition \<Rightarrow> regular language"}*}
+
+text {*
+ The relationship between equivalent classes can be described by an
+ equational system.
+ For example, in equational system \eqref{example_eqns}, $X_0, X_1$ are equivalent
+ classes. The first equation says every string in $X_0$ is obtained either by
+ appending one $b$ to a string in $X_0$ or by appending one $a$ to a string in
+ $X_1$ or just be an empty string (represented by the regular expression $\lambda$). Similary,
+ the second equation tells how the strings inside $X_1$ are composed.
+ \begin{equation}\label{example_eqns}
+ \begin{aligned}
+ X_0 & = X_0 b + X_1 a + \lambda \\
+ X_1 & = X_0 a + X_1 b
+ \end{aligned}
+ \end{equation}
+ The summands on the right hand side is represented by the following data type
+ @{text "rhs_item"}, mnemonic for 'right hand side item'.
+ Generally, there are two kinds of right hand side items, one kind corresponds to
+ pure regular expressions, like the $\lambda$ in \eqref{example_eqns}, the other kind corresponds to
+ transitions from one one equivalent class to another, like the $X_0 b, X_1 a$ etc.
+ *}
datatype rhs_item =
Lam "rexp" (* Lambda *)
- | Trn "string set" "rexp" (* Transition *)
+ | Trn "(string set)" "rexp" (* Transition *)
-fun the_Trn:: "rhs_item \<Rightarrow> (string set \<times> rexp)"
-where "the_Trn (Trn Y r) = (Y, r)"
+text {*
+ In this formalization, pure regular expressions like $\lambda$ is
+ repsented by @{text "Lam(EMPTY)"}, while transitions like $X_0 a$ is represented by $Trn~X_0~(CHAR~a)$.
+ *}
+
+text {*
+ The functions @{text "the_r"} and @{text "the_Trn"} are used to extract
+ subcomponents from right hand side items.
+ *}
fun the_r :: "rhs_item \<Rightarrow> rexp"
where "the_r (Lam r) = r"
+fun the_Trn:: "rhs_item \<Rightarrow> (string set \<times> rexp)"
+where "the_Trn (Trn Y r) = (Y, r)"
+
+text {*
+ Every right hand side item @{text "itm"} defines a string set given
+ @{text "L(itm)"}, defined as:
+*}
overloading L_rhs_e \<equiv> "L:: rhs_item \<Rightarrow> string set"
begin
-fun L_rhs_e:: "rhs_item \<Rightarrow> string set"
-where
- "L_rhs_e (Lam r) = L r" |
- "L_rhs_e (Trn X r) = X ;; L r"
+ fun L_rhs_e:: "rhs_item \<Rightarrow> string set"
+ where
+ "L_rhs_e (Lam r) = L r" |
+ "L_rhs_e (Trn X r) = X ;; L r"
end
+text {*
+ The right hand side of every equation is represented by a set of
+ items. The string set defined by such a set @{text "itms"} is given
+ by @{text "L(itms)"}, defined as:
+*}
+
overloading L_rhs \<equiv> "L:: rhs_item set \<Rightarrow> string set"
begin
-fun L_rhs:: "rhs_item set \<Rightarrow> string set"
-where
- "L_rhs rhs = \<Union> (L ` rhs)"
+ fun L_rhs:: "rhs_item set \<Rightarrow> string set"
+ where "L_rhs rhs = \<Union> (L ` rhs)"
end
+text {*
+ Given a set of equivalent classses @{text "CS"} and one equivalent class @{text "X"} among
+ @{text "CS"}, the term @{text "init_rhs CS X"} is used to extract the right hand side of
+ the equation describing the formation of @{text "X"}. The definition of @{text "init_rhs"}
+ is:
+ *}
+
definition
- "init_rhs CS X \<equiv> if ([] \<in> X)
- then {Lam EMPTY} \<union> {Trn Y (CHAR c)| Y c. Y \<in> CS \<and> Y ;; {[c]} \<subseteq> X}
- else {Trn Y (CHAR c)| Y c. Y \<in> CS \<and> Y ;; {[c]} \<subseteq> X}"
+ "init_rhs CS X \<equiv>
+ if ([] \<in> X) then
+ {Lam(EMPTY)} \<union> {Trn Y (CHAR c) | Y c. Y \<in> CS \<and> Y ;; {[c]} \<subseteq> X}
+ else
+ {Trn Y (CHAR c)| Y c. Y \<in> CS \<and> Y ;; {[c]} \<subseteq> X}"
-definition
- "eqs CS \<equiv> {(X, init_rhs CS X)|X. X \<in> CS}"
+text {*
+ In the definition of @{text "init_rhs"}, the term
+ @{text "{Trn Y (CHAR c)| Y c. Y \<in> CS \<and> Y ;; {[c]} \<subseteq> X}"} appearing on both branches
+ describes the formation of strings in @{text "X"} out of transitions, while
+ the term @{text "{Lam(EMPTY)}"} describes the empty string which is intrinsically contained in
+ @{text "X"} rather than by transition. This @{text "{Lam(EMPTY)}"} corresponds to
+ the $\lambda$ in \eqref{example_eqns}.
+ With the help of @{text "init_rhs"}, the equitional system descrbing the formation of every
+ equivalent class inside @{text "CS"} is given by the following @{text "eqs(CS)"}.
+ *}
+
+definition "eqs CS \<equiv> {(X, init_rhs CS X) | X. X \<in> CS}"
(************ arden's lemma variation ********************)
+text {*
+ The following @{text "items_of rhs X"} returns all @{text "X"}-items in @{text "rhs"}.
+ *}
definition
"items_of rhs X \<equiv> {Trn X r | r. (Trn X r) \<in> rhs}"
+text {*
+ The following @{text "rexp_of rhs X"} combines all regular expressions in @{text "X"}-items
+ using @{text "ALT"} to form a single regular expression.
+ It will be used later to implement @{text "arden_variate"} and @{text "rhs_subst"}.
+ *}
+
+definition
+ "rexp_of rhs X \<equiv> folds ALT NULL ((snd o the_Trn) ` items_of rhs X)"
+
+text {*
+ The following @{text "lam_of rhs"} returns all pure regular expression items in @{text "rhs"}.
+ *}
+
definition
"lam_of rhs \<equiv> {Lam r | r. Lam r \<in> rhs}"
-definition
- "rexp_of rhs X \<equiv> folds ALT NULL ((snd o the_Trn) ` items_of rhs X)"
+text {*
+ The following @{text "rexp_of_lam rhs"} combines pure regular expression items in @{text "rhs"}
+ using @{text "ALT"} to form a single regular expression.
+ When all variables inside @{text "rhs"} are eliminated, @{text "rexp_of_lam rhs"}
+ is used to compute compute the regular expression corresponds to @{text "rhs"}.
+ *}
definition
"rexp_of_lam rhs \<equiv> folds ALT NULL (the_r ` lam_of rhs)"
+text {*
+ The following @{text "attach_rexp rexp' itm"} attach
+ the regular expression @{text "rexp'"} to
+ the right of right hand side item @{text "itm"}.
+ *}
+
fun attach_rexp :: "rexp \<Rightarrow> rhs_item \<Rightarrow> rhs_item"
where
- "attach_rexp r' (Lam r) = Lam (SEQ r r')"
-| "attach_rexp r' (Trn X r) = Trn X (SEQ r r')"
+ "attach_rexp rexp' (Lam rexp) = Lam (SEQ rexp rexp')"
+| "attach_rexp rexp' (Trn X rexp) = Trn X (SEQ rexp rexp')"
+
+text {*
+ The following @{text "append_rhs_rexp rhs rexp"} attaches
+ @{text "rexp"} to every item in @{text "rhs"}.
+ *}
definition
- "append_rhs_rexp rhs r \<equiv> (attach_rexp r) ` rhs"
+ "append_rhs_rexp rhs rexp \<equiv> (attach_rexp rexp) ` rhs"
+text {*
+ With the help of the two functions immediately above, Ardens'
+ transformation on right hand side @{text "rhs"} is implemented
+ by the following function @{text "arden_variate X rhs"}.
+ After this transformation, the recursive occurent of @{text "X"}
+ in @{text "rhs"} will be eliminated, while the
+ string set defined by @{text "rhs"} is kept unchanged.
+ *}
definition
- "arden_variate X rhs \<equiv> append_rhs_rexp (rhs - items_of rhs X) (STAR (rexp_of rhs X))"
+ "arden_variate X rhs \<equiv>
+ append_rhs_rexp (rhs - items_of rhs X) (STAR (rexp_of rhs X))"
(*********** substitution of ES *************)
-text {* rhs_subst rhs X xrhs: substitude all occurence of X in rhs with xrhs *}
+text {*
+ Suppose the equation defining @{text "X"} is $X = xrhs$,
+ the purpose of @{text "rhs_subst"} is to substitute all occurences of @{text "X"} in
+ @{text "rhs"} by @{text "xrhs"}.
+ A litte thought may reveal that the final result
+ should be: first append $(a_1 | a_2 | \ldots | a_n)$ to every item of @{text "xrhs"} and then
+ union the result with all non-@{text "X"}-items of @{text "rhs"}.
+ *}
definition
- "rhs_subst rhs X xrhs \<equiv> (rhs - (items_of rhs X)) \<union> (append_rhs_rexp xrhs (rexp_of rhs X))"
+ "rhs_subst rhs X xrhs \<equiv>
+ (rhs - (items_of rhs X)) \<union> (append_rhs_rexp xrhs (rexp_of rhs X))"
+
+text {*
+ Suppose the equation defining @{text "X"} is $X = xrhs$, the follwing
+ @{text "eqs_subst ES X xrhs"} substitute @{text "xrhs"} into every equation
+ of the equational system @{text "ES"}.
+ *}
definition
"eqs_subst ES X xrhs \<equiv> {(Y, rhs_subst yrhs X xrhs) | Y yrhs. (Y, yrhs) \<in> ES}"
text {*
- Inv: Invairance of the equation-system, during the decrease of the equation-system, Inv holds.
-*}
-
-definition
- "distinct_equas ES \<equiv> \<forall> X rhs rhs'. (X, rhs) \<in> ES \<and> (X, rhs') \<in> ES \<longrightarrow> rhs = rhs'"
-
-definition
- "valid_eqns ES \<equiv> \<forall> X rhs. (X, rhs) \<in> ES \<longrightarrow> (X = L rhs)"
-
-definition
- "rhs_nonempty rhs \<equiv> (\<forall> Y r. Trn Y r \<in> rhs \<longrightarrow> [] \<notin> L r)"
-
-definition
- "ardenable ES \<equiv> \<forall> X rhs. (X, rhs) \<in> ES \<longrightarrow> rhs_nonempty rhs"
-
-definition
- "non_empty ES \<equiv> \<forall> X rhs. (X, rhs) \<in> ES \<longrightarrow> X \<noteq> {}"
-
-definition
- "finite_rhs ES \<equiv> \<forall> X rhs. (X, rhs) \<in> ES \<longrightarrow> finite rhs"
-
-definition
- "classes_of rhs \<equiv> {X. \<exists> r. Trn X r \<in> rhs}"
-
-definition
- "lefts_of ES \<equiv> {Y | Y yrhs. (Y, yrhs) \<in> ES}"
-
-definition
- "self_contained ES \<equiv> \<forall> (X, xrhs) \<in> ES. classes_of xrhs \<subseteq> lefts_of ES"
-
-definition
- "Inv ES \<equiv> valid_eqns ES \<and> finite ES \<and> distinct_equas ES \<and> ardenable ES \<and>
- non_empty ES \<and> finite_rhs ES \<and> self_contained ES"
+ The computation of regular expressions for equivalent classes is accomplished
+ using a iteration principle given by the following lemma.
+ *}
lemma wf_iter [rule_format]:
fixes f
@@ -248,7 +432,88 @@
qed
qed
-text {* ************* basic properties of definitions above ************************ *}
+text {*
+ The @{text "P"} in lemma @{text "wf_iter"} is an invaiant kept throughout the iteration procedure.
+ The particular invariant used to solve our problem is defined by function @{text "Inv(ES)"},
+ an invariant over equal system @{text "ES"}.
+ Every definition starting next till @{text "Inv"} stipulates a property to be satisfied by @{text "ES"}.
+*}
+
+text {*
+ Every variable is defined at most onece in @{text "ES"}.
+ *}
+definition
+ "distinct_equas ES \<equiv>
+ \<forall> X rhs rhs'. (X, rhs) \<in> ES \<and> (X, rhs') \<in> ES \<longrightarrow> rhs = rhs'"
+text {*
+ Every equation in @{text "ES"} (represented by @{text "(X, rhs)"}) is valid, i.e. @{text "(X = L rhs)"}.
+ *}
+definition
+ "valid_eqns ES \<equiv> \<forall> X rhs. (X, rhs) \<in> ES \<longrightarrow> (X = L rhs)"
+
+text {*
+ @{text "rhs_nonempty rhs"} requires regular expressions occuring in transitional
+ items of @{text "rhs"} does not contain empty string. This is necessary for
+ the application of Arden's transformation to @{text "rhs"}.
+ *}
+definition
+ "rhs_nonempty rhs \<equiv> (\<forall> Y r. Trn Y r \<in> rhs \<longrightarrow> [] \<notin> L r)"
+
+text {*
+ @{text "ardenable ES"} requires that Arden's transformation is applicable
+ to every equation of equational system @{text "ES"}.
+ *}
+definition
+ "ardenable ES \<equiv> \<forall> X rhs. (X, rhs) \<in> ES \<longrightarrow> rhs_nonempty rhs"
+
+(* The following non_empty seems useless. *)
+definition
+ "non_empty ES \<equiv> \<forall> X rhs. (X, rhs) \<in> ES \<longrightarrow> X \<noteq> {}"
+
+text {*
+ The following @{text "finite_rhs ES"} requires every equation in @{text "rhs"} be finite.
+ *}
+definition
+ "finite_rhs ES \<equiv> \<forall> X rhs. (X, rhs) \<in> ES \<longrightarrow> finite rhs"
+
+text {*
+ The following @{text "classes_of rhs"} returns all variables (or equivalent classes)
+ occuring in @{text "rhs"}.
+ *}
+definition
+ "classes_of rhs \<equiv> {X. \<exists> r. Trn X r \<in> rhs}"
+
+text {*
+ The following @{text "lefts_of ES"} returns all variables
+ defined by equational system @{text "ES"}.
+ *}
+definition
+ "lefts_of ES \<equiv> {Y | Y yrhs. (Y, yrhs) \<in> ES}"
+
+text {*
+ The following @{text "self_contained ES"} requires that every
+ variable occuring on the right hand side of equations is already defined by some
+ equation in @{text "ES"}.
+ *}
+definition
+ "self_contained ES \<equiv> \<forall> (X, xrhs) \<in> ES. classes_of xrhs \<subseteq> lefts_of ES"
+
+
+text {*
+ The invariant @{text "Inv(ES)"} is obtained by conjunctioning all the previous
+ defined constaints on @{text "ES"}.
+ *}
+definition
+ "Inv ES \<equiv> valid_eqns ES \<and> finite ES \<and> distinct_equas ES \<and> ardenable ES \<and>
+ non_empty ES \<and> finite_rhs ES \<and> self_contained ES"
+
+subsection {* Proof for this direction *}
+
+
+
+text {*
+ The following are some basic properties of the above definitions.
+*}
lemma L_rhs_union_distrib:
" L (A::rhs_item set) \<union> L B = L (A \<union> B)"
@@ -319,11 +584,14 @@
by (auto simp:lefts_of_def)
-text {* ******BEGIN: proving the initial equation-system satisfies Inv ****** *}
+text {*
+ The following several lemmas until @{text "init_ES_satisfy_Inv"} are
+ to prove that initial equational system satisfies invariant @{text "Inv"}.
+ *}
lemma defined_by_str:
"\<lbrakk>s \<in> X; X \<in> UNIV // (\<approx>Lang)\<rbrakk> \<Longrightarrow> X = (\<approx>Lang) `` {s}"
-by (auto simp:quotient_def Image_def str_eq_rel_def str_eq_def)
+by (auto simp:quotient_def Image_def str_eq_rel_def)
lemma every_eqclass_has_transition:
assumes has_str: "s @ [c] \<in> X"
@@ -339,10 +607,10 @@
then have "Y ;; {[c]} \<subseteq> X"
unfolding Y_def Image_def Seq_def
unfolding str_eq_rel_def
- by (auto) (simp add: str_eq_def)
+ by clarsimp
moreover
have "s \<in> Y" unfolding Y_def
- unfolding Image_def str_eq_rel_def str_eq_def by simp
+ unfolding Image_def str_eq_rel_def by simp
ultimately show thesis by (blast intro: that)
qed
@@ -369,7 +637,8 @@
and "Y ;; {[c]} \<subseteq> X"
and "clist \<in> Y"
using decom "(1)" every_eqclass_has_transition by blast
- hence "x \<in> L {Trn Y (CHAR c)| Y c. Y \<in> UNIV // (\<approx>Lang) \<and> Y ;; {[c]} \<subseteq> X}"
+ hence
+ "x \<in> L {Trn Y (CHAR c)| Y c. Y \<in> UNIV // (\<approx>Lang) \<and> Y ;; {[c]} \<subseteq> X}"
using "(1)" decom
by (simp, rule_tac x = "Trn Y (CHAR c)" in exI, simp add:Seq_def)
thus ?thesis using X_in_eqs "(1)"
@@ -412,7 +681,7 @@
moreover have "valid_eqns (eqs (UNIV // (\<approx>Lang)))"
using l_eq_r_in_eqs by (simp add:valid_eqns_def)
moreover have "non_empty (eqs (UNIV // (\<approx>Lang)))"
- by (auto simp:non_empty_def eqs_def quotient_def Image_def str_eq_rel_def str_eq_def)
+ by (auto simp:non_empty_def eqs_def quotient_def Image_def str_eq_rel_def)
moreover have "finite_rhs (eqs (UNIV // (\<approx>Lang)))"
using finite_init_rhs[OF finite_CS]
by (auto simp:finite_rhs_def eqs_def)
@@ -421,8 +690,11 @@
ultimately show ?thesis by (simp add:Inv_def)
qed
-text {* ****** BEGIN: proving every equation-system's iteration step satisfies Inv ***** *}
-
+text {*
+ From this point until @{text "iteration_step"}, we are trying to prove
+ that there exists iteration steps which keep @{text "Inv(ES)"} while
+ decreasing the size of @{text "ES"} with every iteration.
+ *}
lemma arden_variate_keeps_eq:
assumes l_eq_r: "X = L rhs"
and not_empty: "[] \<notin> L (rexp_of rhs X)"
@@ -506,7 +778,8 @@
assumes finite:"finite (ES:: (string set \<times> rhs_item set) set)"
shows "finite (eqs_subst ES Y yrhs)"
proof -
- have "finite {(Ya, rhs_subst yrhsa Y yrhs) |Ya yrhsa. (Ya, yrhsa) \<in> ES}" (is "finite ?A")
+ have "finite {(Ya, rhs_subst yrhsa Y yrhs) |Ya yrhsa. (Ya, yrhsa) \<in> ES}"
+ (is "finite ?A")
proof-
def eqns' \<equiv> "{((Ya::string set), yrhsa)| Ya yrhsa. (Ya, yrhsa) \<in> ES}"
def h \<equiv> "\<lambda> ((Ya::string set), yrhsa). (Ya, rhs_subst yrhsa Y yrhs)"
@@ -537,14 +810,17 @@
by (auto simp:lefts_of_def eqs_subst_def)
lemma rhs_subst_updates_cls:
- "X \<notin> classes_of xrhs \<Longrightarrow> classes_of (rhs_subst rhs X xrhs) = classes_of rhs \<union> classes_of xrhs - {X}"
-apply (simp only:rhs_subst_def append_rhs_keeps_cls classes_of_union_distrib[THEN sym])
+ "X \<notin> classes_of xrhs \<Longrightarrow>
+ classes_of (rhs_subst rhs X xrhs) = classes_of rhs \<union> classes_of xrhs - {X}"
+apply (simp only:rhs_subst_def append_rhs_keeps_cls
+ classes_of_union_distrib[THEN sym])
by (auto simp:classes_of_def items_of_def)
lemma eqs_subst_keeps_self_contained:
fixes Y
assumes sc: "self_contained (ES \<union> {(Y, yrhs)})" (is "self_contained ?A")
- shows "self_contained (eqs_subst ES Y (arden_variate Y yrhs))" (is "self_contained ?B")
+ shows "self_contained (eqs_subst ES Y (arden_variate Y yrhs))"
+ (is "self_contained ?B")
proof-
{ fix X xrhs'
assume "(X, xrhs') \<in> ?B"
@@ -556,15 +832,18 @@
have "lefts_of ?B = lefts_of ES" by (auto simp add:lefts_of_def eqs_subst_def)
moreover have "classes_of xrhs' \<subseteq> lefts_of ES"
proof-
- have "classes_of xrhs' \<subseteq> classes_of xrhs \<union> classes_of (arden_variate Y yrhs) - {Y}"
+ have "classes_of xrhs' \<subseteq>
+ classes_of xrhs \<union> classes_of (arden_variate Y yrhs) - {Y}"
proof-
- have "Y \<notin> classes_of (arden_variate Y yrhs)" using arden_variate_removes_cl by simp
+ have "Y \<notin> classes_of (arden_variate Y yrhs)"
+ using arden_variate_removes_cl by simp
thus ?thesis using xrhs_xrhs' by (auto simp:rhs_subst_updates_cls)
qed
moreover have "classes_of xrhs \<subseteq> lefts_of ES \<union> {Y}" using X_in sc
apply (simp only:self_contained_def lefts_of_union_distrib[THEN sym])
by (drule_tac x = "(X, xrhs)" in bspec, auto simp:lefts_of_def)
- moreover have "classes_of (arden_variate Y yrhs) \<subseteq> lefts_of ES \<union> {Y}" using sc
+ moreover have "classes_of (arden_variate Y yrhs) \<subseteq> lefts_of ES \<union> {Y}"
+ using sc
by (auto simp add:arden_variate_removes_cl self_contained_def lefts_of_def)
ultimately show ?thesis by auto
qed
@@ -577,44 +856,57 @@
assumes Inv_ES: "Inv (ES \<union> {(Y, yrhs)})"
shows "Inv (eqs_subst ES Y (arden_variate Y yrhs))"
proof -
- have finite_yrhs: "finite yrhs" using Inv_ES by (auto simp:Inv_def finite_rhs_def)
- have nonempty_yrhs: "rhs_nonempty yrhs" using Inv_ES by (auto simp:Inv_def ardenable_def)
- have Y_eq_yrhs: "Y = L yrhs" using Inv_ES by (simp only:Inv_def valid_eqns_def, blast)
-
- have "distinct_equas (eqs_subst ES Y (arden_variate Y yrhs))" using Inv_ES
+ have finite_yrhs: "finite yrhs"
+ using Inv_ES by (auto simp:Inv_def finite_rhs_def)
+ have nonempty_yrhs: "rhs_nonempty yrhs"
+ using Inv_ES by (auto simp:Inv_def ardenable_def)
+ have Y_eq_yrhs: "Y = L yrhs"
+ using Inv_ES by (simp only:Inv_def valid_eqns_def, blast)
+ have "distinct_equas (eqs_subst ES Y (arden_variate Y yrhs))"
+ using Inv_ES
by (auto simp:distinct_equas_def eqs_subst_def Inv_def)
- moreover have "finite (eqs_subst ES Y (arden_variate Y yrhs))" using Inv_ES
- by (simp add:Inv_def eqs_subst_keeps_finite)
+ moreover have "finite (eqs_subst ES Y (arden_variate Y yrhs))"
+ using Inv_ES by (simp add:Inv_def eqs_subst_keeps_finite)
moreover have "finite_rhs (eqs_subst ES Y (arden_variate Y yrhs))"
proof-
- have "finite_rhs ES" using Inv_ES by (simp add:Inv_def finite_rhs_def)
+ have "finite_rhs ES" using Inv_ES
+ by (simp add:Inv_def finite_rhs_def)
moreover have "finite (arden_variate Y yrhs)"
proof -
- have "finite yrhs" using Inv_ES by (auto simp:Inv_def finite_rhs_def)
+ have "finite yrhs" using Inv_ES
+ by (auto simp:Inv_def finite_rhs_def)
thus ?thesis using arden_variate_keeps_finite by simp
qed
- ultimately show ?thesis by (simp add:eqs_subst_keeps_finite_rhs)
+ ultimately show ?thesis
+ by (simp add:eqs_subst_keeps_finite_rhs)
qed
moreover have "ardenable (eqs_subst ES Y (arden_variate Y yrhs))"
proof -
{ fix X rhs
assume "(X, rhs) \<in> ES"
- hence "rhs_nonempty rhs" using prems Inv_ES by (simp add:Inv_def ardenable_def)
- with nonempty_yrhs have "rhs_nonempty (rhs_subst rhs Y (arden_variate Y yrhs))"
- by (simp add:nonempty_yrhs rhs_subst_keeps_nonempty arden_variate_keeps_nonempty)
+ hence "rhs_nonempty rhs" using prems Inv_ES
+ by (simp add:Inv_def ardenable_def)
+ with nonempty_yrhs
+ have "rhs_nonempty (rhs_subst rhs Y (arden_variate Y yrhs))"
+ by (simp add:nonempty_yrhs
+ rhs_subst_keeps_nonempty arden_variate_keeps_nonempty)
} thus ?thesis by (auto simp add:ardenable_def eqs_subst_def)
qed
moreover have "valid_eqns (eqs_subst ES Y (arden_variate Y yrhs))"
proof-
- have "Y = L (arden_variate Y yrhs)" using Y_eq_yrhs Inv_ES finite_yrhs nonempty_yrhs
- by (rule_tac arden_variate_keeps_eq, (simp add:rexp_of_empty)+)
+ have "Y = L (arden_variate Y yrhs)"
+ using Y_eq_yrhs Inv_ES finite_yrhs nonempty_yrhs
+ by (rule_tac arden_variate_keeps_eq, (simp add:rexp_of_empty)+)
thus ?thesis using Inv_ES
- by (clarsimp simp add:valid_eqns_def eqs_subst_def rhs_subst_keeps_eq Inv_def finite_rhs_def
+ by (clarsimp simp add:valid_eqns_def
+ eqs_subst_def rhs_subst_keeps_eq Inv_def finite_rhs_def
simp del:L_rhs.simps)
qed
- moreover have non_empty_subst: "non_empty (eqs_subst ES Y (arden_variate Y yrhs))"
+ moreover have
+ non_empty_subst: "non_empty (eqs_subst ES Y (arden_variate Y yrhs))"
using Inv_ES by (auto simp:Inv_def non_empty_def eqs_subst_def)
- moreover have self_subst: "self_contained (eqs_subst ES Y (arden_variate Y yrhs))"
+ moreover
+ have self_subst: "self_contained (eqs_subst ES Y (arden_variate Y yrhs))"
using Inv_ES eqs_subst_keeps_self_contained by (simp add:Inv_def)
ultimately show ?thesis using Inv_ES by (simp add:Inv_def)
qed
@@ -642,7 +934,8 @@
proof-
have "card (S - {e}) > 0"
proof -
- have "card S > 1" using card e_in finite by (case_tac "card S", auto)
+ have "card S > 1" using card e_in finite
+ by (case_tac "card S", auto)
thus ?thesis using finite e_in by auto
qed
hence "S - {e} \<noteq> {}" using finite by (rule_tac notI, simp)
@@ -653,10 +946,12 @@
assumes Inv_ES: "Inv ES"
and X_in_ES: "(X, xrhs) \<in> ES"
and not_T: "card ES \<noteq> 1"
- shows "\<exists> ES'. (Inv ES' \<and> (\<exists> xrhs'.(X, xrhs') \<in> ES')) \<and> (card ES', card ES) \<in> less_than" (is "\<exists> ES'. ?P ES'")
+ shows "\<exists> ES'. (Inv ES' \<and> (\<exists> xrhs'.(X, xrhs') \<in> ES')) \<and>
+ (card ES', card ES) \<in> less_than" (is "\<exists> ES'. ?P ES'")
proof -
have finite_ES: "finite ES" using Inv_ES by (simp add:Inv_def)
- then obtain Y yrhs where Y_in_ES: "(Y, yrhs) \<in> ES" and not_eq: "(X, xrhs) \<noteq> (Y, yrhs)"
+ then obtain Y yrhs
+ where Y_in_ES: "(Y, yrhs) \<in> ES" and not_eq: "(X, xrhs) \<noteq> (Y, yrhs)"
using not_T X_in_ES by (drule_tac card_noteq_1_has_more, auto)
def ES' == "ES - {(Y, yrhs)}"
let ?ES'' = "eqs_subst ES' Y (arden_variate Y yrhs)"
@@ -679,12 +974,17 @@
thus ?thesis by blast
qed
-text {* ***** END: proving every equation-system's iteration step satisfies Inv ************** *}
+text {*
+ From this point until @{text "hard_direction"}, the hard direction is proved
+ through a simple application of the iteration principle.
+*}
lemma iteration_conc:
assumes history: "Inv ES"
and X_in_ES: "\<exists> xrhs. (X, xrhs) \<in> ES"
- shows "\<exists> ES'. (Inv ES' \<and> (\<exists> xrhs'. (X, xrhs') \<in> ES')) \<and> card ES' = 1" (is "\<exists> ES'. ?P ES'")
+ shows
+ "\<exists> ES'. (Inv ES' \<and> (\<exists> xrhs'. (X, xrhs') \<in> ES')) \<and> card ES' = 1"
+ (is "\<exists> ES'. ?P ES'")
proof (cases "card ES = 1")
case True
thus ?thesis using history X_in_ES
@@ -706,26 +1006,31 @@
have "L (rexp_of_lam ?A) = L (lam_of ?A)"
proof(rule rexp_of_lam_eq_lam_set)
show "finite (arden_variate X xrhs)" using Inv_ES ES_single
- by (rule_tac arden_variate_keeps_finite, auto simp add:Inv_def finite_rhs_def)
+ by (rule_tac arden_variate_keeps_finite,
+ auto simp add:Inv_def finite_rhs_def)
qed
also have "\<dots> = L ?A"
proof-
have "lam_of ?A = ?A"
proof-
have "classes_of ?A = {}" using Inv_ES ES_single
- by (simp add:arden_variate_removes_cl self_contained_def Inv_def lefts_of_def)
- thus ?thesis by (auto simp only:lam_of_def classes_of_def, case_tac x, auto)
+ by (simp add:arden_variate_removes_cl
+ self_contained_def Inv_def lefts_of_def)
+ thus ?thesis
+ by (auto simp only:lam_of_def classes_of_def, case_tac x, auto)
qed
thus ?thesis by simp
qed
also have "\<dots> = X"
proof(rule arden_variate_keeps_eq [THEN sym])
- show "X = L xrhs" using Inv_ES ES_single by (auto simp only:Inv_def valid_eqns_def)
+ show "X = L xrhs" using Inv_ES ES_single
+ by (auto simp only:Inv_def valid_eqns_def)
next
from Inv_ES ES_single show "[] \<notin> L (rexp_of xrhs X)"
by(simp add:Inv_def ardenable_def rexp_of_empty finite_rhs_def)
next
- from Inv_ES ES_single show "finite xrhs" by (simp add:Inv_def finite_rhs_def)
+ from Inv_ES ES_single show "finite xrhs"
+ by (simp add:Inv_def finite_rhs_def)
qed
finally show ?thesis by simp
qed
@@ -750,79 +1055,73 @@
by (rule last_cl_exists_rexp)
qed
+lemma finals_in_partitions:
+ "finals Lang \<subseteq> (UNIV // (\<approx>Lang))"
+ by (auto simp:finals_def quotient_def)
+
theorem hard_direction:
assumes finite_CS: "finite (UNIV // (\<approx>Lang))"
shows "\<exists> (reg::rexp). Lang = L reg"
proof -
have "\<forall> X \<in> (UNIV // (\<approx>Lang)). \<exists> (reg::rexp). X = L reg"
using finite_CS every_eqcl_has_reg by blast
- then obtain f where f_prop: "\<forall> X \<in> (UNIV // (\<approx>Lang)). X = L ((f X)::rexp)"
+ then obtain f
+ where f_prop: "\<forall> X \<in> (UNIV // (\<approx>Lang)). X = L ((f X)::rexp)"
by (auto dest:bchoice)
- def rs \<equiv> "f ` {X. final X Lang}"
- have "Lang = \<Union> {X. final X Lang}" using lang_is_union_of_finals by simp
+ def rs \<equiv> "f ` (finals Lang)"
+ have "Lang = \<Union> (finals Lang)" using lang_is_union_of_finals by auto
also have "\<dots> = L (folds ALT NULL rs)"
proof -
- have "finite {X. final X Lang}" using finite_CS by (auto simp:final_def)
- thus ?thesis using f_prop by (auto simp:rs_def final_def)
+ have "finite rs"
+ proof -
+ have "finite (finals Lang)"
+ using finite_CS finals_in_partitions[of "Lang"]
+ by (erule_tac finite_subset, simp)
+ thus ?thesis using rs_def by auto
+ qed
+ thus ?thesis
+ using f_prop rs_def finals_in_partitions[of "Lang"] by auto
qed
finally show ?thesis by blast
qed
-section {* regular \<Rightarrow> finite*}
+section {* Direction: @{text "regular language \<Rightarrow>finite partition"} *}
+
+subsection {* The scheme for this direction *}
-lemma quot_empty_subset:
- "UNIV // (\<approx>{[]}) \<subseteq> {{[]}, UNIV - {[]}}"
-proof
- fix x
- assume "x \<in> UNIV // \<approx>{[]}"
- then obtain y where h: "x = {z. (y, z) \<in> \<approx>{[]}}" unfolding quotient_def Image_def by blast
- show "x \<in> {{[]}, UNIV - {[]}}"
- proof (cases "y = []")
- case True with h
- have "x = {[]}" by (auto simp:str_eq_rel_def str_eq_def)
- thus ?thesis by simp
- next
- case False with h
- have "x = UNIV - {[]}" by (auto simp:str_eq_rel_def str_eq_def)
- thus ?thesis by simp
- qed
-qed
+text {*
+ The following convenient notation @{text "x \<approx>Lang y"} means:
+ string @{text "x"} and @{text "y"} are equivalent with respect to
+ language @{text "Lang"}.
+ *}
+
+definition
+ str_eq ("_ \<approx>_ _")
+where
+ "x \<approx>Lang y \<equiv> (x, y) \<in> (\<approx>Lang)"
-lemma quot_char_subset:
- "UNIV // (\<approx>{[c]}) \<subseteq> {{[]},{[c]}, UNIV - {[], [c]}}"
-proof
- fix x
- assume "x \<in> UNIV // \<approx>{[c]}"
- then obtain y where h: "x = {z. (y, z) \<in> \<approx>{[c]}}" unfolding quotient_def Image_def by blast
- show "x \<in> {{[]},{[c]}, UNIV - {[], [c]}}"
- proof -
- { assume "y = []" hence "x = {[]}" using h by (auto simp:str_eq_rel_def str_eq_def)
- } moreover {
- assume "y = [c]" hence "x = {[c]}" using h
- by (auto dest!:spec[where x = "[]"] simp:str_eq_rel_def str_eq_def)
- } moreover {
- assume "y \<noteq> []" and "y \<noteq> [c]"
- hence "\<forall> z. (y @ z) \<noteq> [c]" by (case_tac y, auto)
- moreover have "\<And> p. (p \<noteq> [] \<and> p \<noteq> [c]) = (\<forall> q. p @ q \<noteq> [c])" by (case_tac p, auto)
- ultimately have "x = UNIV - {[],[c]}" using h
- by (auto simp add:str_eq_rel_def str_eq_def)
- } ultimately show ?thesis by blast
- qed
-qed
+text {*
+ The very basic scheme to show the finiteness of the partion generated by a language @{text "Lang"}
+ is by attaching tags to every string. The set of tags are carfully choosen to make it finite.
+ If it can be proved that strings with the same tag are equivlent with respect @{text "Lang"},
+ then the partition given rise by @{text "Lang"} must be finite. The reason for this is a lemma
+ in standard library (@{text "finite_imageD"}), which says: if the image of an injective
+ function on a set @{text "A"} is finite, then @{text "A"} is finite. It can be shown that
+ the function obtained by llifting @{text "tag"}
+ to the level of equalent classes (i.e. @{text "((op `) tag)"}) is injective
+ (by lemma @{text "tag_image_injI"}) and the image of this function is finite
+ (with the help of lemma @{text "finite_tag_imageI"}).
-text {* *************** Some common lemmas for following ALT, SEQ & STAR cases ******************* *}
-
-lemma finite_tag_imageI:
- "finite (range tag) \<Longrightarrow> finite (((op `) tag) ` S)"
-apply (rule_tac B = "Pow (tag ` UNIV)" in finite_subset)
-by (auto simp add:image_def Pow_def)
+ BUT, I think this argument can be encapsulated by one lemma instead of the current presentation.
+ *}
lemma eq_class_equalI:
- "\<lbrakk>X \<in> UNIV // \<approx>lang; Y \<in> UNIV // \<approx>lang; x \<in> X; y \<in> Y; x \<approx>lang y\<rbrakk> \<Longrightarrow> X = Y"
+ "\<lbrakk>X \<in> UNIV // \<approx>lang; Y \<in> UNIV // \<approx>lang; x \<in> X; y \<in> Y; x \<approx>lang y\<rbrakk>
+ \<Longrightarrow> X = Y"
by (auto simp:quotient_def str_eq_rel_def str_eq_def)
lemma tag_image_injI:
- assumes str_inj: "\<And> m n. tag m = tag (n::string) \<Longrightarrow> m \<approx>lang n"
+ assumes str_inj: "\<And> x y. tag x = tag (y::string) \<Longrightarrow> x \<approx>lang y"
shows "inj_on ((op `) tag) (UNIV // \<approx>lang)"
proof-
{ fix X Y
@@ -838,7 +1137,17 @@
thus ?thesis unfolding inj_on_def by auto
qed
-text {* **************** the SEQ case ************************ *}
+lemma finite_tag_imageI:
+ "finite (range tag) \<Longrightarrow> finite (((op `) tag) ` S)"
+apply (rule_tac B = "Pow (tag ` UNIV)" in finite_subset)
+by (auto simp add:image_def Pow_def)
+
+
+subsection {* A small theory for list difference *}
+
+text {*
+ The notion of list diffrence is need to make proofs more readable.
+ *}
(* list_diff:: list substract, once different return tailer *)
fun list_diff :: "'a list \<Rightarrow> 'a list \<Rightarrow> 'a list" (infix "-" 51)
@@ -884,29 +1193,99 @@
by (clarsimp, auto simp:prefix_def)
lemma app_eq_dest:
- "x @ y = m @ n \<Longrightarrow> (x \<le> m \<and> (m - x) @ n = y) \<or> (m \<le> x \<and> (x - m) @ y = n)"
+ "x @ y = m @ n \<Longrightarrow>
+ (x \<le> m \<and> (m - x) @ n = y) \<or> (m \<le> x \<and> (x - m) @ y = n)"
by (frule_tac app_eq_cases, auto elim:prefixE)
+subsection {* Lemmas for basic cases *}
+
+text {*
+ The the final result of this direction is in @{text "easier_direction"}, which
+ is an induction on the structure of regular expressions. There is one case
+ for each regular expression operator. For basic operators such as @{text "NULL, EMPTY, CHAR c"},
+ the finiteness of their language partition can be established directly with no need
+ of taggiing. This section contains several technical lemma for these base cases.
+
+ The inductive cases involve operators @{text "ALT, SEQ"} and @{text "STAR"}.
+ Tagging functions need to be defined individually for each of them. There will be one
+ dedicated section for each of these cases, and each section goes virtually the same way:
+ gives definition of the tagging function and prove that strings
+ with the same tag are equivalent.
+ *}
+
+lemma quot_empty_subset:
+ "UNIV // (\<approx>{[]}) \<subseteq> {{[]}, UNIV - {[]}}"
+proof
+ fix x
+ assume "x \<in> UNIV // \<approx>{[]}"
+ then obtain y where h: "x = {z. (y, z) \<in> \<approx>{[]}}"
+ unfolding quotient_def Image_def by blast
+ show "x \<in> {{[]}, UNIV - {[]}}"
+ proof (cases "y = []")
+ case True with h
+ have "x = {[]}" by (auto simp:str_eq_rel_def)
+ thus ?thesis by simp
+ next
+ case False with h
+ have "x = UNIV - {[]}" by (auto simp:str_eq_rel_def)
+ thus ?thesis by simp
+ qed
+qed
+
+lemma quot_char_subset:
+ "UNIV // (\<approx>{[c]}) \<subseteq> {{[]},{[c]}, UNIV - {[], [c]}}"
+proof
+ fix x
+ assume "x \<in> UNIV // \<approx>{[c]}"
+ then obtain y where h: "x = {z. (y, z) \<in> \<approx>{[c]}}"
+ unfolding quotient_def Image_def by blast
+ show "x \<in> {{[]},{[c]}, UNIV - {[], [c]}}"
+ proof -
+ { assume "y = []" hence "x = {[]}" using h
+ by (auto simp:str_eq_rel_def)
+ } moreover {
+ assume "y = [c]" hence "x = {[c]}" using h
+ by (auto dest!:spec[where x = "[]"] simp:str_eq_rel_def)
+ } moreover {
+ assume "y \<noteq> []" and "y \<noteq> [c]"
+ hence "\<forall> z. (y @ z) \<noteq> [c]" by (case_tac y, auto)
+ moreover have "\<And> p. (p \<noteq> [] \<and> p \<noteq> [c]) = (\<forall> q. p @ q \<noteq> [c])"
+ by (case_tac p, auto)
+ ultimately have "x = UNIV - {[],[c]}" using h
+ by (auto simp add:str_eq_rel_def)
+ } ultimately show ?thesis by blast
+ qed
+qed
+
+subsection {* The case for @{text "SEQ"}*}
+
definition
- "tag_str_SEQ L\<^isub>1 L\<^isub>2 x \<equiv> ((\<approx>L\<^isub>1) `` {x}, {(\<approx>L\<^isub>2) `` {x - xa}| xa. xa \<le> x \<and> xa \<in> L\<^isub>1})"
+ "tag_str_SEQ L\<^isub>1 L\<^isub>2 x \<equiv>
+ ((\<approx>L\<^isub>1) `` {x}, {(\<approx>L\<^isub>2) `` {x - xa}| xa. xa \<le> x \<and> xa \<in> L\<^isub>1})"
lemma tag_str_seq_range_finite:
- "\<lbrakk>finite (UNIV // \<approx>L\<^isub>1); finite (UNIV // \<approx>L\<^isub>2)\<rbrakk> \<Longrightarrow> finite (range (tag_str_SEQ L\<^isub>1 L\<^isub>2))"
+ "\<lbrakk>finite (UNIV // \<approx>L\<^isub>1); finite (UNIV // \<approx>L\<^isub>2)\<rbrakk>
+ \<Longrightarrow> finite (range (tag_str_SEQ L\<^isub>1 L\<^isub>2))"
apply (rule_tac B = "(UNIV // \<approx>L\<^isub>1) \<times> (Pow (UNIV // \<approx>L\<^isub>2))" in finite_subset)
by (auto simp:tag_str_SEQ_def Image_def quotient_def split:if_splits)
lemma append_seq_elim:
assumes "x @ y \<in> L\<^isub>1 ;; L\<^isub>2"
- shows "(\<exists> xa \<le> x. xa \<in> L\<^isub>1 \<and> (x - xa) @ y \<in> L\<^isub>2) \<or> (\<exists> ya \<le> y. (x @ ya) \<in> L\<^isub>1 \<and> (y - ya) \<in> L\<^isub>2)"
+ shows "(\<exists> xa \<le> x. xa \<in> L\<^isub>1 \<and> (x - xa) @ y \<in> L\<^isub>2) \<or>
+ (\<exists> ya \<le> y. (x @ ya) \<in> L\<^isub>1 \<and> (y - ya) \<in> L\<^isub>2)"
proof-
- from assms obtain s\<^isub>1 s\<^isub>2 where "x @ y = s\<^isub>1 @ s\<^isub>2" and in_seq: "s\<^isub>1 \<in> L\<^isub>1 \<and> s\<^isub>2 \<in> L\<^isub>2"
+ from assms obtain s\<^isub>1 s\<^isub>2
+ where "x @ y = s\<^isub>1 @ s\<^isub>2"
+ and in_seq: "s\<^isub>1 \<in> L\<^isub>1 \<and> s\<^isub>2 \<in> L\<^isub>2"
by (auto simp:Seq_def)
hence "(x \<le> s\<^isub>1 \<and> (s\<^isub>1 - x) @ s\<^isub>2 = y) \<or> (s\<^isub>1 \<le> x \<and> (x - s\<^isub>1) @ y = s\<^isub>2)"
using app_eq_dest by auto
- moreover have "\<lbrakk>x \<le> s\<^isub>1; (s\<^isub>1 - x) @ s\<^isub>2 = y\<rbrakk> \<Longrightarrow> \<exists> ya \<le> y. (x @ ya) \<in> L\<^isub>1 \<and> (y - ya) \<in> L\<^isub>2" using in_seq
- by (rule_tac x = "s\<^isub>1 - x" in exI, auto elim:prefixE)
- moreover have "\<lbrakk>s\<^isub>1 \<le> x; (x - s\<^isub>1) @ y = s\<^isub>2\<rbrakk> \<Longrightarrow> \<exists> xa \<le> x. xa \<in> L\<^isub>1 \<and> (x - xa) @ y \<in> L\<^isub>2" using in_seq
- by (rule_tac x = s\<^isub>1 in exI, auto)
+ moreover have "\<lbrakk>x \<le> s\<^isub>1; (s\<^isub>1 - x) @ s\<^isub>2 = y\<rbrakk> \<Longrightarrow>
+ \<exists> ya \<le> y. (x @ ya) \<in> L\<^isub>1 \<and> (y - ya) \<in> L\<^isub>2"
+ using in_seq by (rule_tac x = "s\<^isub>1 - x" in exI, auto elim:prefixE)
+ moreover have "\<lbrakk>s\<^isub>1 \<le> x; (x - s\<^isub>1) @ y = s\<^isub>2\<rbrakk> \<Longrightarrow>
+ \<exists> xa \<le> x. xa \<in> L\<^isub>1 \<and> (x - xa) @ y \<in> L\<^isub>2"
+ using in_seq by (rule_tac x = s\<^isub>1 in exI, auto)
ultimately show ?thesis by blast
qed
@@ -918,7 +1297,8 @@
and tag_xy: "tag_str_SEQ L\<^isub>1 L\<^isub>2 x = tag_str_SEQ L\<^isub>1 L\<^isub>2 y"
have"y @ z \<in> L\<^isub>1 ;; L\<^isub>2"
proof-
- have "(\<exists> xa \<le> x. xa \<in> L\<^isub>1 \<and> (x - xa) @ z \<in> L\<^isub>2) \<or> (\<exists> za \<le> z. (x @ za) \<in> L\<^isub>1 \<and> (z - za) \<in> L\<^isub>2)"
+ have "(\<exists> xa \<le> x. xa \<in> L\<^isub>1 \<and> (x - xa) @ z \<in> L\<^isub>2) \<or>
+ (\<exists> za \<le> z. (x @ za) \<in> L\<^isub>1 \<and> (z - za) \<in> L\<^isub>2)"
using xz_in_seq append_seq_elim by simp
moreover {
fix xa
@@ -928,7 +1308,8 @@
have "\<exists> ya. ya \<le> y \<and> ya \<in> L\<^isub>1 \<and> (x - xa) \<approx>L\<^isub>2 (y - ya)"
proof -
have "{\<approx>L\<^isub>2 `` {x - xa} |xa. xa \<le> x \<and> xa \<in> L\<^isub>1} =
- {\<approx>L\<^isub>2 `` {y - xa} |xa. xa \<le> y \<and> xa \<in> L\<^isub>1}" (is "?Left = ?Right")
+ {\<approx>L\<^isub>2 `` {y - xa} |xa. xa \<le> y \<and> xa \<in> L\<^isub>1}"
+ (is "?Left = ?Right")
using h1 tag_xy by (auto simp:tag_str_SEQ_def)
moreover have "\<approx>L\<^isub>2 `` {x - xa} \<in> ?Left" using h1 h2 by auto
ultimately have "\<approx>L\<^isub>2 `` {x - xa} \<in> ?Right" by simp
@@ -942,10 +1323,13 @@
assume h1: "za \<le> z" and h2: "(x @ za) \<in> L\<^isub>1" and h3: "z - za \<in> L\<^isub>2"
hence "y @ za \<in> L\<^isub>1"
proof-
- have "\<approx>L\<^isub>1 `` {x} = \<approx>L\<^isub>1 `` {y}" using h1 tag_xy by (auto simp:tag_str_SEQ_def)
- with h2 show ?thesis by (auto simp:Image_def str_eq_rel_def str_eq_def)
+ have "\<approx>L\<^isub>1 `` {x} = \<approx>L\<^isub>1 `` {y}"
+ using h1 tag_xy by (auto simp:tag_str_SEQ_def)
+ with h2 show ?thesis
+ by (auto simp:Image_def str_eq_rel_def str_eq_def)
qed
- with h1 h3 have "y @ z \<in> L\<^isub>1 ;; L\<^isub>2" by (drule_tac A = L\<^isub>1 in seq_intro, auto elim:prefixE)
+ with h1 h3 have "y @ z \<in> L\<^isub>1 ;; L\<^isub>2"
+ by (drule_tac A = L\<^isub>1 in seq_intro, auto elim:prefixE)
}
ultimately show ?thesis by blast
qed
@@ -958,7 +1342,8 @@
and finite2: "finite (UNIV // \<approx>L\<^isub>2)"
shows "finite (UNIV // \<approx>(L\<^isub>1 ;; L\<^isub>2))"
proof(rule_tac f = "(op `) (tag_str_SEQ L\<^isub>1 L\<^isub>2)" in finite_imageD)
- show "finite (op ` (tag_str_SEQ L\<^isub>1 L\<^isub>2) ` UNIV // \<approx>L\<^isub>1 ;; L\<^isub>2)" using finite1 finite2
+ show "finite (op ` (tag_str_SEQ L\<^isub>1 L\<^isub>2) ` UNIV // \<approx>L\<^isub>1 ;; L\<^isub>2)"
+ using finite1 finite2
by (auto intro:finite_tag_imageI tag_str_seq_range_finite)
next
show "inj_on (op ` (tag_str_SEQ L\<^isub>1 L\<^isub>2)) (UNIV // \<approx>L\<^isub>1 ;; L\<^isub>2)"
@@ -967,13 +1352,14 @@
by (auto intro:tag_image_injI tag_str_SEQ_injI simp:)
qed
-text {* **************** the ALT case ************************ *}
+subsection {* The case for @{text "ALT"} *}
definition
"tag_str_ALT L\<^isub>1 L\<^isub>2 (x::string) \<equiv> ((\<approx>L\<^isub>1) `` {x}, (\<approx>L\<^isub>2) `` {x})"
lemma tag_str_alt_range_finite:
- "\<lbrakk>finite (UNIV // \<approx>L\<^isub>1); finite (UNIV // \<approx>L\<^isub>2)\<rbrakk> \<Longrightarrow> finite (range (tag_str_ALT L\<^isub>1 L\<^isub>2))"
+ "\<lbrakk>finite (UNIV // \<approx>L\<^isub>1); finite (UNIV // \<approx>L\<^isub>2)\<rbrakk>
+ \<Longrightarrow> finite (range (tag_str_ALT L\<^isub>1 L\<^isub>2))"
apply (rule_tac B = "(UNIV // \<approx>L\<^isub>1) \<times> (UNIV // \<approx>L\<^isub>2)" in finite_subset)
by (auto simp:tag_str_ALT_def Image_def quotient_def)
@@ -982,20 +1368,33 @@
and finite2: "finite (UNIV // \<approx>L\<^isub>2)"
shows "finite (UNIV // \<approx>(L\<^isub>1 \<union> L\<^isub>2))"
proof(rule_tac f = "(op `) (tag_str_ALT L\<^isub>1 L\<^isub>2)" in finite_imageD)
- show "finite (op ` (tag_str_ALT L\<^isub>1 L\<^isub>2) ` UNIV // \<approx>L\<^isub>1 \<union> L\<^isub>2)" using finite1 finite2
+ show "finite (op ` (tag_str_ALT L\<^isub>1 L\<^isub>2) ` UNIV // \<approx>L\<^isub>1 \<union> L\<^isub>2)"
+ using finite1 finite2
by (auto intro:finite_tag_imageI tag_str_alt_range_finite)
next
show "inj_on (op ` (tag_str_ALT L\<^isub>1 L\<^isub>2)) (UNIV // \<approx>L\<^isub>1 \<union> L\<^isub>2)"
proof-
- have "\<And>m n. tag_str_ALT L\<^isub>1 L\<^isub>2 m = tag_str_ALT L\<^isub>1 L\<^isub>2 n \<Longrightarrow> m \<approx>(L\<^isub>1 \<union> L\<^isub>2) n"
+ have "\<And>m n. tag_str_ALT L\<^isub>1 L\<^isub>2 m = tag_str_ALT L\<^isub>1 L\<^isub>2 n
+ \<Longrightarrow> m \<approx>(L\<^isub>1 \<union> L\<^isub>2) n"
unfolding tag_str_ALT_def str_eq_def Image_def str_eq_rel_def by auto
thus ?thesis by (auto intro:tag_image_injI)
qed
qed
-text {* **************** the Star case ****************** *}
+
+subsection {*
+ The case for @{text "STAR"}
+ *}
-lemma finite_set_has_max: "\<lbrakk>finite A; A \<noteq> {}\<rbrakk> \<Longrightarrow> (\<exists> max \<in> A. \<forall> a \<in> A. f a <= (f max :: nat))"
+text {*
+ This turned out to be the most tricky case.
+ *} (* I will make some illustrations for it. *)
+
+definition
+ "tag_str_STAR L\<^isub>1 x \<equiv> {(\<approx>L\<^isub>1) `` {x - xa} | xa. xa < x \<and> xa \<in> L\<^isub>1\<star>}"
+
+lemma finite_set_has_max: "\<lbrakk>finite A; A \<noteq> {}\<rbrakk> \<Longrightarrow>
+ (\<exists> max \<in> A. \<forall> a \<in> A. f a <= (f max :: nat))"
proof (induct rule:finite.induct)
case emptyI thus ?case by simp
next
@@ -1005,7 +1404,9 @@
case True thus ?thesis by (rule_tac x = a in bexI, auto)
next
case False
- with prems obtain max where h1: "max \<in> A" and h2: "\<forall>a\<in>A. f a \<le> f max" by blast
+ with prems obtain max
+ where h1: "max \<in> A"
+ and h2: "\<forall>a\<in>A. f a \<le> f max" by blast
show ?thesis
proof (cases "f a \<le> f max")
assume "f a \<le> f max"
@@ -1017,30 +1418,17 @@
qed
qed
-lemma star_intro1[rule_format]: "x \<in> lang\<star> \<Longrightarrow> \<forall> y. y \<in> lang\<star> \<longrightarrow> x @ y \<in> lang\<star>"
-by (erule Star.induct, auto)
-
-lemma star_intro2: "y \<in> lang \<Longrightarrow> y \<in> lang\<star>"
-by (drule step[of y lang "[]"], auto simp:start)
-
-lemma star_intro3[rule_format]: "x \<in> lang\<star> \<Longrightarrow> \<forall>y . y \<in> lang \<longrightarrow> x @ y \<in> lang\<star>"
-by (erule Star.induct, auto intro:star_intro2)
-
-lemma star_decom: "\<lbrakk>x \<in> lang\<star>; x \<noteq> []\<rbrakk> \<Longrightarrow>(\<exists> a b. x = a @ b \<and> a \<noteq> [] \<and> a \<in> lang \<and> b \<in> lang\<star>)"
-by (induct x rule: Star.induct, simp, blast)
-
lemma finite_strict_prefix_set: "finite {xa. xa < (x::string)}"
apply (induct x rule:rev_induct, simp)
apply (subgoal_tac "{xa. xa < xs @ [x]} = {xa. xa < xs} \<union> {xs}")
by (auto simp:strict_prefix_def)
-definition
- "tag_str_STAR L\<^isub>1 x \<equiv> {(\<approx>L\<^isub>1) `` {x - xa} | xa. xa < x \<and> xa \<in> L\<^isub>1\<star>}"
lemma tag_str_star_range_finite:
"finite (UNIV // \<approx>L\<^isub>1) \<Longrightarrow> finite (range (tag_str_STAR L\<^isub>1))"
apply (rule_tac B = "Pow (UNIV // \<approx>L\<^isub>1)" in finite_subset)
-by (auto simp:tag_str_STAR_def Image_def quotient_def split:if_splits)
+by (auto simp:tag_str_STAR_def Image_def
+ quotient_def split:if_splits)
lemma tag_str_STAR_injI:
"tag_str_STAR L\<^isub>1 m = tag_str_STAR L\<^isub>1 n \<Longrightarrow> m \<approx>(L\<^isub>1\<star>) n"
@@ -1051,58 +1439,76 @@
have "y @ z \<in> L\<^isub>1\<star>"
proof(cases "x = []")
case True
- with tag_xy have "y = []" by (auto simp:tag_str_STAR_def strict_prefix_def)
+ with tag_xy have "y = []"
+ by (auto simp:tag_str_STAR_def strict_prefix_def)
thus ?thesis using xz_in_star True by simp
next
case False
- obtain x_max where h1: "x_max < x" and h2: "x_max \<in> L\<^isub>1\<star>" and h3: "(x - x_max) @ z \<in> L\<^isub>1\<star>"
- and h4:"\<forall> xa < x. xa \<in> L\<^isub>1\<star> \<and> (x - xa) @ z \<in> L\<^isub>1\<star> \<longrightarrow> length xa \<le> length x_max"
+ obtain x_max
+ where h1: "x_max < x"
+ and h2: "x_max \<in> L\<^isub>1\<star>"
+ and h3: "(x - x_max) @ z \<in> L\<^isub>1\<star>"
+ and h4:"\<forall> xa < x. xa \<in> L\<^isub>1\<star> \<and> (x - xa) @ z \<in> L\<^isub>1\<star>
+ \<longrightarrow> length xa \<le> length x_max"
proof-
let ?S = "{xa. xa < x \<and> xa \<in> L\<^isub>1\<star> \<and> (x - xa) @ z \<in> L\<^isub>1\<star>}"
have "finite ?S"
- by (rule_tac B = "{xa. xa < x}" in finite_subset, auto simp:finite_strict_prefix_set)
+ by (rule_tac B = "{xa. xa < x}" in finite_subset,
+ auto simp:finite_strict_prefix_set)
moreover have "?S \<noteq> {}" using False xz_in_star
by (simp, rule_tac x = "[]" in exI, auto simp:strict_prefix_def)
- ultimately have "\<exists> max \<in> ?S. \<forall> a \<in> ?S. length a \<le> length max" using finite_set_has_max by blast
+ ultimately have "\<exists> max \<in> ?S. \<forall> a \<in> ?S. length a \<le> length max"
+ using finite_set_has_max by blast
with prems show ?thesis by blast
qed
- obtain ya where h5: "ya < y" and h6: "ya \<in> L\<^isub>1\<star>" and h7: "(x - x_max) \<approx>L\<^isub>1 (y - ya)"
+ obtain ya
+ where h5: "ya < y" and h6: "ya \<in> L\<^isub>1\<star>" and h7: "(x - x_max) \<approx>L\<^isub>1 (y - ya)"
proof-
from tag_xy have "{\<approx>L\<^isub>1 `` {x - xa} |xa. xa < x \<and> xa \<in> L\<^isub>1\<star>} =
{\<approx>L\<^isub>1 `` {y - xa} |xa. xa < y \<and> xa \<in> L\<^isub>1\<star>}" (is "?left = ?right")
by (auto simp:tag_str_STAR_def)
moreover have "\<approx>L\<^isub>1 `` {x - x_max} \<in> ?left" using h1 h2 by auto
ultimately have "\<approx>L\<^isub>1 `` {x - x_max} \<in> ?right" by simp
- with prems show ?thesis apply (simp add:Image_def str_eq_rel_def str_eq_def) by blast
+ with prems show ?thesis apply
+ (simp add:Image_def str_eq_rel_def str_eq_def) by blast
qed
have "(y - ya) @ z \<in> L\<^isub>1\<star>"
proof-
- from h3 h1 obtain a b where a_in: "a \<in> L\<^isub>1" and a_neq: "a \<noteq> []" and b_in: "b \<in> L\<^isub>1\<star>"
+ from h3 h1 obtain a b where a_in: "a \<in> L\<^isub>1"
+ and a_neq: "a \<noteq> []" and b_in: "b \<in> L\<^isub>1\<star>"
and ab_max: "(x - x_max) @ z = a @ b"
by (drule_tac star_decom, auto simp:strict_prefix_def elim:prefixE)
have "(x - x_max) \<le> a \<and> (a - (x - x_max)) @ b = z"
proof -
- have "((x - x_max) \<le> a \<and> (a - (x - x_max)) @ b = z) \<or> (a < (x - x_max) \<and> ((x - x_max) - a) @ z = b)"
+ have "((x - x_max) \<le> a \<and> (a - (x - x_max)) @ b = z) \<or>
+ (a < (x - x_max) \<and> ((x - x_max) - a) @ z = b)"
using app_eq_dest[OF ab_max] by (auto simp:strict_prefix_def)
moreover {
assume np: "a < (x - x_max)" and b_eqs: " ((x - x_max) - a) @ z = b"
have "False"
proof -
let ?x_max' = "x_max @ a"
- have "?x_max' < x" using np h1 by (clarsimp simp:strict_prefix_def diff_prefix)
- moreover have "?x_max' \<in> L\<^isub>1\<star>" using a_in h2 by (simp add:star_intro3)
- moreover have "(x - ?x_max') @ z \<in> L\<^isub>1\<star>" using b_eqs b_in np h1 by (simp add:diff_diff_appd)
- moreover have "\<not> (length ?x_max' \<le> length x_max)" using a_neq by simp
+ have "?x_max' < x"
+ using np h1 by (clarsimp simp:strict_prefix_def diff_prefix)
+ moreover have "?x_max' \<in> L\<^isub>1\<star>"
+ using a_in h2 by (simp add:star_intro3)
+ moreover have "(x - ?x_max') @ z \<in> L\<^isub>1\<star>"
+ using b_eqs b_in np h1 by (simp add:diff_diff_appd)
+ moreover have "\<not> (length ?x_max' \<le> length x_max)"
+ using a_neq by simp
ultimately show ?thesis using h4 by blast
qed
} ultimately show ?thesis by blast
qed
- then obtain za where z_decom: "z = za @ b" and x_za: "(x - x_max) @ za \<in> L\<^isub>1"
+ then obtain za where z_decom: "z = za @ b"
+ and x_za: "(x - x_max) @ za \<in> L\<^isub>1"
using a_in by (auto elim:prefixE)
- from x_za h7 have "(y - ya) @ za \<in> L\<^isub>1" by (auto simp:str_eq_def)
+ from x_za h7 have "(y - ya) @ za \<in> L\<^isub>1"
+ by (auto simp:str_eq_def str_eq_rel_def)
with z_decom b_in show ?thesis by (auto dest!:step[of "(y - ya) @ za"])
qed
- with h5 h6 show ?thesis by (drule_tac star_intro1, auto simp:strict_prefix_def elim:prefixE)
+ with h5 h6 show ?thesis
+ by (drule_tac star_intro1, auto simp:strict_prefix_def elim:prefixE)
qed
} thus "tag_str_STAR L\<^isub>1 m = tag_str_STAR L\<^isub>1 n \<Longrightarrow> m \<approx>(L\<^isub>1\<star>) n"
by (auto simp add:str_eq_def str_eq_rel_def)
@@ -1119,9 +1525,11 @@
by (auto intro:tag_image_injI tag_str_STAR_injI)
qed
-text {* **************** the Other Direction ************ *}
+subsection {*
+ The main lemma
+ *}
-lemma other_direction:
+lemma easier_directio\<nu>:
"Lang = L (r::rexp) \<Longrightarrow> finite (UNIV // (\<approx>Lang))"
proof (induct arbitrary:Lang rule:rexp.induct)
case NULL
@@ -1130,27 +1538,33 @@
with prems show "?case" by (auto intro:finite_subset)
next
case EMPTY
- have "UNIV // (\<approx>{[]}) \<subseteq> {{[]}, UNIV - {[]}}" by (rule quot_empty_subset)
+ have "UNIV // (\<approx>{[]}) \<subseteq> {{[]}, UNIV - {[]}}"
+ by (rule quot_empty_subset)
with prems show ?case by (auto intro:finite_subset)
next
case (CHAR c)
- have "UNIV // (\<approx>{[c]}) \<subseteq> {{[]},{[c]}, UNIV - {[], [c]}}" by (rule quot_char_subset)
+ have "UNIV // (\<approx>{[c]}) \<subseteq> {{[]},{[c]}, UNIV - {[], [c]}}"
+ by (rule quot_char_subset)
with prems show ?case by (auto intro:finite_subset)
next
case (SEQ r\<^isub>1 r\<^isub>2)
- have "\<lbrakk>finite (UNIV // \<approx>(L r\<^isub>1)); finite (UNIV // \<approx>(L r\<^isub>2))\<rbrakk> \<Longrightarrow> finite (UNIV // \<approx>(L r\<^isub>1 ;; L r\<^isub>2))"
+ have "\<lbrakk>finite (UNIV // \<approx>(L r\<^isub>1)); finite (UNIV // \<approx>(L r\<^isub>2))\<rbrakk>
+ \<Longrightarrow> finite (UNIV // \<approx>(L r\<^isub>1 ;; L r\<^isub>2))"
by (erule quot_seq_finiteI, simp)
with prems show ?case by simp
next
case (ALT r\<^isub>1 r\<^isub>2)
- have "\<lbrakk>finite (UNIV // \<approx>(L r\<^isub>1)); finite (UNIV // \<approx>(L r\<^isub>2))\<rbrakk> \<Longrightarrow> finite (UNIV // \<approx>(L r\<^isub>1 \<union> L r\<^isub>2))"
+ have "\<lbrakk>finite (UNIV // \<approx>(L r\<^isub>1)); finite (UNIV // \<approx>(L r\<^isub>2))\<rbrakk>
+ \<Longrightarrow> finite (UNIV // \<approx>(L r\<^isub>1 \<union> L r\<^isub>2))"
by (erule quot_union_finiteI, simp)
with prems show ?case by simp
next
case (STAR r)
- have "finite (UNIV // \<approx>(L r)) \<Longrightarrow> finite (UNIV // \<approx>((L r)\<star>))"
+ have "finite (UNIV // \<approx>(L r))
+ \<Longrightarrow> finite (UNIV // \<approx>((L r)\<star>))"
by (erule quot_star_finiteI)
with prems show ?case by simp
qed
-end
\ No newline at end of file
+end
+
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/pres/IsaMakefile Mon Jan 24 11:29:55 2011 +0000
@@ -0,0 +1,31 @@
+
+## targets
+
+default: ListP
+images: ListP
+test:
+
+all: images test
+
+
+## global settings
+
+SRC = $(ISABELLE_HOME)/src
+OUT = $(ISABELLE_OUTPUT)
+LOG = $(OUT)/log
+
+USEDIR = $(ISABELLE_TOOL) usedir -v true -i true -d pdf ## -D generated
+
+
+## ListP
+
+ListP: $(OUT)/ListP
+
+$(OUT)/ListP: ROOT.ML document/root.tex *.thy
+ @$(USEDIR) -b HOL ListP
+
+
+## clean
+
+clean:
+ @rm -f $(OUT)/ListP
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/pres/ListP.thy Mon Jan 24 11:29:55 2011 +0000
@@ -0,0 +1,4 @@
+theory ListP
+imports Main List_Prefix
+begin
+end
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/pres/ROOT.ML Mon Jan 24 11:29:55 2011 +0000
@@ -0,0 +1,6 @@
+(*
+ no_document use_thys ["This_Theory1", "This_Theory2"];
+ use_thys ["That_Theory1", "That_Theory2", "That_Theory3"];
+*)
+
+use_thy "ListP";;
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/pres/document/root.tex Mon Jan 24 11:29:55 2011 +0000
@@ -0,0 +1,63 @@
+\documentclass[11pt,a4paper]{article}
+\usepackage{isabelle,isabellesym}
+
+% further packages required for unusual symbols (see also
+% isabellesym.sty), use only when needed
+
+%\usepackage{amssymb}
+ %for \<leadsto>, \<box>, \<diamond>, \<sqsupset>, \<mho>, \<Join>,
+ %\<lhd>, \<lesssim>, \<greatersim>, \<lessapprox>, \<greaterapprox>,
+ %\<triangleq>, \<yen>, \<lozenge>
+
+%\usepackage[greek,english]{babel}
+ %option greek for \<euro>
+ %option english (default language) for \<guillemotleft>, \<guillemotright>
+
+%\usepackage[latin1]{inputenc}
+ %for \<onesuperior>, \<onequarter>, \<twosuperior>, \<onehalf>,
+ %\<threesuperior>, \<threequarters>, \<degree>
+
+%\usepackage[only,bigsqcap]{stmaryrd}
+ %for \<Sqinter>
+
+%\usepackage{eufrak}
+ %for \<AA> ... \<ZZ>, \<aa> ... \<zz> (also included in amssymb)
+
+%\usepackage{textcomp}
+ %for \<cent>, \<currency>
+
+% this should be the last package used
+\usepackage{pdfsetup}
+
+% urls in roman style, theory text in math-similar italics
+\urlstyle{rm}
+\isabellestyle{it}
+
+% for uniform font size
+%\renewcommand{\isastyle}{\isastyleminor}
+
+
+\begin{document}
+
+\title{ListP}
+\author{By xingyuan}
+\maketitle
+
+\tableofcontents
+
+% sane default for proof documents
+\parindent 0pt\parskip 0.5ex
+
+% generated text of all theories
+\input{session}
+
+% optional bibliography
+%\bibliographystyle{abbrv}
+%\bibliography{root}
+
+\end{document}
+
+%%% Local Variables:
+%%% mode: latex
+%%% TeX-master: t
+%%% End:
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/tphols-2011/ROOT.ML Mon Jan 24 11:29:55 2011 +0000
@@ -0,0 +1,5 @@
+(*
+ no_document use_thys ["This_Theory1", "This_Theory2"];
+ use_thys ["That_Theory1", "That_Theory2", "That_Theory3"];
+*)
+use_thys ["../Myhill"];;
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/tphols-2011/document/root.tex Mon Jan 24 11:29:55 2011 +0000
@@ -0,0 +1,65 @@
+\documentclass[11pt,a4paper]{article}
+\usepackage{isabelle,isabellesym}
+\usepackage{amsmath}
+%\usepackage[pdftex]{hyperref}
+
+% further packages required for unusual symbols (see also
+% isabellesym.sty), use only when needed
+
+%\usepackage{amssymb}
+ %for \<leadsto>, \<box>, \<diamond>, \<sqsupset>, \<mho>, \<Join>,
+ %\<lhd>, \<lesssim>, \<greatersim>, \<lessapprox>, \<greaterapprox>,
+ %\<triangleq>, \<yen>, \<lozenge>
+
+%\usepackage[greek,english]{babel}
+ %option greek for \<euro>
+ %option english (default language) for \<guillemotleft>, \<guillemotright>
+
+%\usepackage[latin1]{inputenc}
+ %for \<onesuperior>, \<onequarter>, \<twosuperior>, \<onehalf>,
+ %\<threesuperior>, \<threequarters>, \<degree>
+
+%\usepackage[only,bigsqcap]{stmaryrd}
+ %for \<Sqinter>
+
+%\usepackage{eufrak}
+ %for \<AA> ... \<ZZ>, \<aa> ... \<zz> (also included in amssymb)
+
+%\usepackage{textcomp}
+ %for \<cent>, \<currency>
+
+% this should be the last package used
+\usepackage{pdfsetup}
+
+% urls in roman style, theory text in math-similar italics
+\urlstyle{rm}
+\isabellestyle{it}
+
+% for uniform font size
+%\renewcommand{\isastyle}{\isastyleminor}
+
+
+\begin{document}
+
+\title{tphols-2011}
+\author{By xingyuan}
+\maketitle
+
+\tableofcontents
+
+% sane default for proof documents
+\parindent 0pt\parskip 0.5ex
+
+% generated text of all theories
+\input{session}
+
+% optional bibliography
+%\bibliographystyle{abbrv}
+%\bibliography{root}
+
+\end{document}
+
+%%% Local Variables:
+%%% mode: latex
+%%% TeX-master: t
+%%% End:
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/tphols-2011/generated/List_Prefix.tex Mon Jan 24 11:29:55 2011 +0000
@@ -0,0 +1,1578 @@
+%
+\begin{isabellebody}%
+\def\isabellecontext{List{\isacharunderscore}Prefix}%
+%
+\isamarkupheader{List prefixes and postfixes%
+}
+\isamarkuptrue%
+%
+\isadelimtheory
+%
+\endisadelimtheory
+%
+\isatagtheory
+\isacommand{theory}\isamarkupfalse%
+\ List{\isacharunderscore}Prefix\isanewline
+\isakeyword{imports}\ List\ Main\isanewline
+\isakeyword{begin}%
+\endisatagtheory
+{\isafoldtheory}%
+%
+\isadelimtheory
+%
+\endisadelimtheory
+%
+\isamarkupsubsection{Prefix order on lists%
+}
+\isamarkuptrue%
+\isacommand{instantiation}\isamarkupfalse%
+\ list\ {\isacharcolon}{\isacharcolon}\ {\isacharparenleft}type{\isacharparenright}\ order\isanewline
+\isakeyword{begin}\isanewline
+\isanewline
+\isacommand{definition}\isamarkupfalse%
+\isanewline
+\ \ prefix{\isacharunderscore}def\ {\isacharbrackleft}code\ del{\isacharbrackright}{\isacharcolon}\ {\isachardoublequoteopen}xs\ {\isasymle}\ ys\ {\isacharequal}\ {\isacharparenleft}{\isasymexists}zs{\isachardot}\ ys\ {\isacharequal}\ xs\ {\isacharat}\ zs{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\isanewline
+\isacommand{definition}\isamarkupfalse%
+\isanewline
+\ \ strict{\isacharunderscore}prefix{\isacharunderscore}def\ {\isacharbrackleft}code\ del{\isacharbrackright}{\isacharcolon}\ {\isachardoublequoteopen}xs\ {\isacharless}\ ys\ {\isacharequal}\ {\isacharparenleft}xs\ {\isasymle}\ ys\ {\isasymand}\ xs\ {\isasymnoteq}\ {\isacharparenleft}ys{\isacharcolon}{\isacharcolon}{\isacharprime}a\ list{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\isanewline
+\isacommand{instance}\isamarkupfalse%
+\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ intro{\isacharunderscore}classes\ {\isacharparenleft}auto\ simp\ add{\isacharcolon}\ prefix{\isacharunderscore}def\ strict{\isacharunderscore}prefix{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{end}\isamarkupfalse%
+\isanewline
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ prefixI\ {\isacharbrackleft}intro{\isacharquery}{\isacharbrackright}{\isacharcolon}\ {\isachardoublequoteopen}ys\ {\isacharequal}\ xs\ {\isacharat}\ zs\ {\isacharequal}{\isacharequal}{\isachargreater}\ xs\ {\isasymle}\ ys{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{unfolding}\isamarkupfalse%
+\ prefix{\isacharunderscore}def\ \isacommand{by}\isamarkupfalse%
+\ blast%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ prefixE\ {\isacharbrackleft}elim{\isacharquery}{\isacharbrackright}{\isacharcolon}\isanewline
+\ \ \isakeyword{assumes}\ {\isachardoublequoteopen}xs\ {\isasymle}\ ys{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{obtains}\ zs\ \isakeyword{where}\ {\isachardoublequoteopen}ys\ {\isacharequal}\ xs\ {\isacharat}\ zs{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{using}\isamarkupfalse%
+\ assms\ \isacommand{unfolding}\isamarkupfalse%
+\ prefix{\isacharunderscore}def\ \isacommand{by}\isamarkupfalse%
+\ blast%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ strict{\isacharunderscore}prefixI{\isacharprime}\ {\isacharbrackleft}intro{\isacharquery}{\isacharbrackright}{\isacharcolon}\ {\isachardoublequoteopen}ys\ {\isacharequal}\ xs\ {\isacharat}\ z\ {\isacharhash}\ zs\ {\isacharequal}{\isacharequal}{\isachargreater}\ xs\ {\isacharless}\ ys{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{unfolding}\isamarkupfalse%
+\ strict{\isacharunderscore}prefix{\isacharunderscore}def\ prefix{\isacharunderscore}def\ \isacommand{by}\isamarkupfalse%
+\ blast%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ strict{\isacharunderscore}prefixE{\isacharprime}\ {\isacharbrackleft}elim{\isacharquery}{\isacharbrackright}{\isacharcolon}\isanewline
+\ \ \isakeyword{assumes}\ {\isachardoublequoteopen}xs\ {\isacharless}\ ys{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{obtains}\ z\ zs\ \isakeyword{where}\ {\isachardoublequoteopen}ys\ {\isacharequal}\ xs\ {\isacharat}\ z\ {\isacharhash}\ zs{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+\ {\isacharminus}\isanewline
+\ \ \isacommand{from}\isamarkupfalse%
+\ {\isacharbackquoteopen}xs\ {\isacharless}\ ys{\isacharbackquoteclose}\ \isacommand{obtain}\isamarkupfalse%
+\ us\ \isakeyword{where}\ {\isachardoublequoteopen}ys\ {\isacharequal}\ xs\ {\isacharat}\ us{\isachardoublequoteclose}\ \isakeyword{and}\ {\isachardoublequoteopen}xs\ {\isasymnoteq}\ ys{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{unfolding}\isamarkupfalse%
+\ strict{\isacharunderscore}prefix{\isacharunderscore}def\ prefix{\isacharunderscore}def\ \isacommand{by}\isamarkupfalse%
+\ blast\isanewline
+\ \ \isacommand{with}\isamarkupfalse%
+\ that\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp\ add{\isacharcolon}\ neq{\isacharunderscore}Nil{\isacharunderscore}conv{\isacharparenright}\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ strict{\isacharunderscore}prefixI\ {\isacharbrackleft}intro{\isacharquery}{\isacharbrackright}{\isacharcolon}\ {\isachardoublequoteopen}xs\ {\isasymle}\ ys\ {\isacharequal}{\isacharequal}{\isachargreater}\ xs\ {\isasymnoteq}\ ys\ {\isacharequal}{\isacharequal}{\isachargreater}\ xs\ {\isacharless}\ {\isacharparenleft}ys{\isacharcolon}{\isacharcolon}{\isacharprime}a\ list{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{unfolding}\isamarkupfalse%
+\ strict{\isacharunderscore}prefix{\isacharunderscore}def\ \isacommand{by}\isamarkupfalse%
+\ blast%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ strict{\isacharunderscore}prefixE\ {\isacharbrackleft}elim{\isacharquery}{\isacharbrackright}{\isacharcolon}\isanewline
+\ \ \isakeyword{fixes}\ xs\ ys\ {\isacharcolon}{\isacharcolon}\ {\isachardoublequoteopen}{\isacharprime}a\ list{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{assumes}\ {\isachardoublequoteopen}xs\ {\isacharless}\ ys{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{obtains}\ {\isachardoublequoteopen}xs\ {\isasymle}\ ys{\isachardoublequoteclose}\ \isakeyword{and}\ {\isachardoublequoteopen}xs\ {\isasymnoteq}\ ys{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{using}\isamarkupfalse%
+\ assms\ \isacommand{unfolding}\isamarkupfalse%
+\ strict{\isacharunderscore}prefix{\isacharunderscore}def\ \isacommand{by}\isamarkupfalse%
+\ blast%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isamarkupsubsection{Basic properties of prefixes%
+}
+\isamarkuptrue%
+\isacommand{theorem}\isamarkupfalse%
+\ Nil{\isacharunderscore}prefix\ {\isacharbrackleft}iff{\isacharbrackright}{\isacharcolon}\ {\isachardoublequoteopen}{\isacharbrackleft}{\isacharbrackright}\ {\isasymle}\ xs{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}simp\ add{\isacharcolon}\ prefix{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{theorem}\isamarkupfalse%
+\ prefix{\isacharunderscore}Nil\ {\isacharbrackleft}simp{\isacharbrackright}{\isacharcolon}\ {\isachardoublequoteopen}{\isacharparenleft}xs\ {\isasymle}\ {\isacharbrackleft}{\isacharbrackright}{\isacharparenright}\ {\isacharequal}\ {\isacharparenleft}xs\ {\isacharequal}\ {\isacharbrackleft}{\isacharbrackright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}induct\ xs{\isacharparenright}\ {\isacharparenleft}simp{\isacharunderscore}all\ add{\isacharcolon}\ prefix{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ prefix{\isacharunderscore}snoc\ {\isacharbrackleft}simp{\isacharbrackright}{\isacharcolon}\ {\isachardoublequoteopen}{\isacharparenleft}xs\ {\isasymle}\ ys\ {\isacharat}\ {\isacharbrackleft}y{\isacharbrackright}{\isacharparenright}\ {\isacharequal}\ {\isacharparenleft}xs\ {\isacharequal}\ ys\ {\isacharat}\ {\isacharbrackleft}y{\isacharbrackright}\ {\isasymor}\ xs\ {\isasymle}\ ys{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{assume}\isamarkupfalse%
+\ {\isachardoublequoteopen}xs\ {\isasymle}\ ys\ {\isacharat}\ {\isacharbrackleft}y{\isacharbrackright}{\isachardoublequoteclose}\isanewline
+\ \ \isacommand{then}\isamarkupfalse%
+\ \isacommand{obtain}\isamarkupfalse%
+\ zs\ \isakeyword{where}\ zs{\isacharcolon}\ {\isachardoublequoteopen}ys\ {\isacharat}\ {\isacharbrackleft}y{\isacharbrackright}\ {\isacharequal}\ xs\ {\isacharat}\ zs{\isachardoublequoteclose}\ \isacommand{{\isachardot}{\isachardot}}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{show}\isamarkupfalse%
+\ {\isachardoublequoteopen}xs\ {\isacharequal}\ ys\ {\isacharat}\ {\isacharbrackleft}y{\isacharbrackright}\ {\isasymor}\ xs\ {\isasymle}\ ys{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}metis\ append{\isacharunderscore}Nil{\isadigit{2}}\ butlast{\isacharunderscore}append\ butlast{\isacharunderscore}snoc\ prefixI\ zs{\isacharparenright}\isanewline
+\isacommand{next}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{assume}\isamarkupfalse%
+\ {\isachardoublequoteopen}xs\ {\isacharequal}\ ys\ {\isacharat}\ {\isacharbrackleft}y{\isacharbrackright}\ {\isasymor}\ xs\ {\isasymle}\ ys{\isachardoublequoteclose}\isanewline
+\ \ \isacommand{then}\isamarkupfalse%
+\ \isacommand{show}\isamarkupfalse%
+\ {\isachardoublequoteopen}xs\ {\isasymle}\ ys\ {\isacharat}\ {\isacharbrackleft}y{\isacharbrackright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}metis\ order{\isacharunderscore}eq{\isacharunderscore}iff\ strict{\isacharunderscore}prefixE\ strict{\isacharunderscore}prefixI{\isacharprime}\ xt{\isadigit{1}}{\isacharparenleft}{\isadigit{7}}{\isacharparenright}{\isacharparenright}\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ Cons{\isacharunderscore}prefix{\isacharunderscore}Cons\ {\isacharbrackleft}simp{\isacharbrackright}{\isacharcolon}\ {\isachardoublequoteopen}{\isacharparenleft}x\ {\isacharhash}\ xs\ {\isasymle}\ y\ {\isacharhash}\ ys{\isacharparenright}\ {\isacharequal}\ {\isacharparenleft}x\ {\isacharequal}\ y\ {\isasymand}\ xs\ {\isasymle}\ ys{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp\ add{\isacharcolon}\ prefix{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ same{\isacharunderscore}prefix{\isacharunderscore}prefix\ {\isacharbrackleft}simp{\isacharbrackright}{\isacharcolon}\ {\isachardoublequoteopen}{\isacharparenleft}xs\ {\isacharat}\ ys\ {\isasymle}\ xs\ {\isacharat}\ zs{\isacharparenright}\ {\isacharequal}\ {\isacharparenleft}ys\ {\isasymle}\ zs{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}induct\ xs{\isacharparenright}\ simp{\isacharunderscore}all%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ same{\isacharunderscore}prefix{\isacharunderscore}nil\ {\isacharbrackleft}iff{\isacharbrackright}{\isacharcolon}\ {\isachardoublequoteopen}{\isacharparenleft}xs\ {\isacharat}\ ys\ {\isasymle}\ xs{\isacharparenright}\ {\isacharequal}\ {\isacharparenleft}ys\ {\isacharequal}\ {\isacharbrackleft}{\isacharbrackright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}metis\ append{\isacharunderscore}Nil{\isadigit{2}}\ append{\isacharunderscore}self{\isacharunderscore}conv\ order{\isacharunderscore}eq{\isacharunderscore}iff\ prefixI{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ prefix{\isacharunderscore}prefix\ {\isacharbrackleft}simp{\isacharbrackright}{\isacharcolon}\ {\isachardoublequoteopen}xs\ {\isasymle}\ ys\ {\isacharequal}{\isacharequal}{\isachargreater}\ xs\ {\isasymle}\ ys\ {\isacharat}\ zs{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}metis\ order{\isacharunderscore}le{\isacharunderscore}less{\isacharunderscore}trans\ prefixI\ strict{\isacharunderscore}prefixE\ strict{\isacharunderscore}prefixI{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ append{\isacharunderscore}prefixD{\isacharcolon}\ {\isachardoublequoteopen}xs\ {\isacharat}\ ys\ {\isasymle}\ zs\ {\isasymLongrightarrow}\ xs\ {\isasymle}\ zs{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp\ add{\isacharcolon}\ prefix{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{theorem}\isamarkupfalse%
+\ prefix{\isacharunderscore}Cons{\isacharcolon}\ {\isachardoublequoteopen}{\isacharparenleft}xs\ {\isasymle}\ y\ {\isacharhash}\ ys{\isacharparenright}\ {\isacharequal}\ {\isacharparenleft}xs\ {\isacharequal}\ {\isacharbrackleft}{\isacharbrackright}\ {\isasymor}\ {\isacharparenleft}{\isasymexists}zs{\isachardot}\ xs\ {\isacharequal}\ y\ {\isacharhash}\ zs\ {\isasymand}\ zs\ {\isasymle}\ ys{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}cases\ xs{\isacharparenright}\ {\isacharparenleft}auto\ simp\ add{\isacharcolon}\ prefix{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{theorem}\isamarkupfalse%
+\ prefix{\isacharunderscore}append{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}{\isacharparenleft}xs\ {\isasymle}\ ys\ {\isacharat}\ zs{\isacharparenright}\ {\isacharequal}\ {\isacharparenleft}xs\ {\isasymle}\ ys\ {\isasymor}\ {\isacharparenleft}{\isasymexists}us{\isachardot}\ xs\ {\isacharequal}\ ys\ {\isacharat}\ us\ {\isasymand}\ us\ {\isasymle}\ zs{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}induct\ zs\ rule{\isacharcolon}\ rev{\isacharunderscore}induct{\isacharparenright}\isanewline
+\ \ \ \isacommand{apply}\isamarkupfalse%
+\ force\isanewline
+\ \ \isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}simp\ del{\isacharcolon}\ append{\isacharunderscore}assoc\ add{\isacharcolon}\ append{\isacharunderscore}assoc\ {\isacharbrackleft}symmetric{\isacharbrackright}{\isacharparenright}\isanewline
+\ \ \isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}metis\ append{\isacharunderscore}eq{\isacharunderscore}appendI{\isacharparenright}\isanewline
+\ \ \isacommand{done}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ append{\isacharunderscore}one{\isacharunderscore}prefix{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}xs\ {\isasymle}\ ys\ {\isacharequal}{\isacharequal}{\isachargreater}\ length\ xs\ {\isacharless}\ length\ ys\ {\isacharequal}{\isacharequal}{\isachargreater}\ xs\ {\isacharat}\ {\isacharbrackleft}ys\ {\isacharbang}\ length\ xs{\isacharbrackright}\ {\isasymle}\ ys{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{unfolding}\isamarkupfalse%
+\ prefix{\isacharunderscore}def\isanewline
+\ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}metis\ Cons{\isacharunderscore}eq{\isacharunderscore}appendI\ append{\isacharunderscore}eq{\isacharunderscore}appendI\ append{\isacharunderscore}eq{\isacharunderscore}conv{\isacharunderscore}conj\isanewline
+\ \ \ \ eq{\isacharunderscore}Nil{\isacharunderscore}appendI\ nth{\isacharunderscore}drop{\isacharprime}{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{theorem}\isamarkupfalse%
+\ prefix{\isacharunderscore}length{\isacharunderscore}le{\isacharcolon}\ {\isachardoublequoteopen}xs\ {\isasymle}\ ys\ {\isacharequal}{\isacharequal}{\isachargreater}\ length\ xs\ {\isasymle}\ length\ ys{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp\ add{\isacharcolon}\ prefix{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ prefix{\isacharunderscore}same{\isacharunderscore}cases{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}{\isacharparenleft}xs\isactrlisub {\isadigit{1}}{\isacharcolon}{\isacharcolon}{\isacharprime}a\ list{\isacharparenright}\ {\isasymle}\ ys\ {\isasymLongrightarrow}\ xs\isactrlisub {\isadigit{2}}\ {\isasymle}\ ys\ {\isasymLongrightarrow}\ xs\isactrlisub {\isadigit{1}}\ {\isasymle}\ xs\isactrlisub {\isadigit{2}}\ {\isasymor}\ xs\isactrlisub {\isadigit{2}}\ {\isasymle}\ xs\isactrlisub {\isadigit{1}}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{unfolding}\isamarkupfalse%
+\ prefix{\isacharunderscore}def\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}metis\ append{\isacharunderscore}eq{\isacharunderscore}append{\isacharunderscore}conv{\isadigit{2}}{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ set{\isacharunderscore}mono{\isacharunderscore}prefix{\isacharcolon}\ {\isachardoublequoteopen}xs\ {\isasymle}\ ys\ {\isasymLongrightarrow}\ set\ xs\ {\isasymsubseteq}\ set\ ys{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp\ add{\isacharcolon}\ prefix{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ take{\isacharunderscore}is{\isacharunderscore}prefix{\isacharcolon}\ {\isachardoublequoteopen}take\ n\ xs\ {\isasymle}\ xs{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{unfolding}\isamarkupfalse%
+\ prefix{\isacharunderscore}def\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}metis\ append{\isacharunderscore}take{\isacharunderscore}drop{\isacharunderscore}id{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ map{\isacharunderscore}prefixI{\isacharcolon}\ {\isachardoublequoteopen}xs\ {\isasymle}\ ys\ {\isasymLongrightarrow}\ map\ f\ xs\ {\isasymle}\ map\ f\ ys{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}\ prefix{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ prefix{\isacharunderscore}length{\isacharunderscore}less{\isacharcolon}\ {\isachardoublequoteopen}xs\ {\isacharless}\ ys\ {\isasymLongrightarrow}\ length\ xs\ {\isacharless}\ length\ ys{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}\ strict{\isacharunderscore}prefix{\isacharunderscore}def\ prefix{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ strict{\isacharunderscore}prefix{\isacharunderscore}simps\ {\isacharbrackleft}simp{\isacharbrackright}{\isacharcolon}\isanewline
+\ \ \ \ {\isachardoublequoteopen}xs\ {\isacharless}\ {\isacharbrackleft}{\isacharbrackright}\ {\isacharequal}\ False{\isachardoublequoteclose}\isanewline
+\ \ \ \ {\isachardoublequoteopen}{\isacharbrackleft}{\isacharbrackright}\ {\isacharless}\ {\isacharparenleft}x\ {\isacharhash}\ xs{\isacharparenright}\ {\isacharequal}\ True{\isachardoublequoteclose}\isanewline
+\ \ \ \ {\isachardoublequoteopen}{\isacharparenleft}x\ {\isacharhash}\ xs{\isacharparenright}\ {\isacharless}\ {\isacharparenleft}y\ {\isacharhash}\ ys{\isacharparenright}\ {\isacharequal}\ {\isacharparenleft}x\ {\isacharequal}\ y\ {\isasymand}\ xs\ {\isacharless}\ ys{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}simp{\isacharunderscore}all\ add{\isacharcolon}\ strict{\isacharunderscore}prefix{\isacharunderscore}def\ cong{\isacharcolon}\ conj{\isacharunderscore}cong{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ take{\isacharunderscore}strict{\isacharunderscore}prefix{\isacharcolon}\ {\isachardoublequoteopen}xs\ {\isacharless}\ ys\ {\isasymLongrightarrow}\ take\ n\ xs\ {\isacharless}\ ys{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}induct\ n\ arbitrary{\isacharcolon}\ xs\ ys{\isacharparenright}\isanewline
+\ \ \ \isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}case{\isacharunderscore}tac\ ys{\isacharcomma}\ simp{\isacharunderscore}all{\isacharparenright}{\isacharbrackleft}{\isadigit{1}}{\isacharbrackright}\isanewline
+\ \ \isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}metis\ order{\isacharunderscore}less{\isacharunderscore}trans\ strict{\isacharunderscore}prefixI\ take{\isacharunderscore}is{\isacharunderscore}prefix{\isacharparenright}\isanewline
+\ \ \isacommand{done}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ not{\isacharunderscore}prefix{\isacharunderscore}cases{\isacharcolon}\isanewline
+\ \ \isakeyword{assumes}\ pfx{\isacharcolon}\ {\isachardoublequoteopen}{\isasymnot}\ ps\ {\isasymle}\ ls{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{obtains}\isanewline
+\ \ \ \ {\isacharparenleft}c{\isadigit{1}}{\isacharparenright}\ {\isachardoublequoteopen}ps\ {\isasymnoteq}\ {\isacharbrackleft}{\isacharbrackright}{\isachardoublequoteclose}\ \isakeyword{and}\ {\isachardoublequoteopen}ls\ {\isacharequal}\ {\isacharbrackleft}{\isacharbrackright}{\isachardoublequoteclose}\isanewline
+\ \ {\isacharbar}\ {\isacharparenleft}c{\isadigit{2}}{\isacharparenright}\ a\ as\ x\ xs\ \isakeyword{where}\ {\isachardoublequoteopen}ps\ {\isacharequal}\ a{\isacharhash}as{\isachardoublequoteclose}\ \isakeyword{and}\ {\isachardoublequoteopen}ls\ {\isacharequal}\ x{\isacharhash}xs{\isachardoublequoteclose}\ \isakeyword{and}\ {\isachardoublequoteopen}x\ {\isacharequal}\ a{\isachardoublequoteclose}\ \isakeyword{and}\ {\isachardoublequoteopen}{\isasymnot}\ as\ {\isasymle}\ xs{\isachardoublequoteclose}\isanewline
+\ \ {\isacharbar}\ {\isacharparenleft}c{\isadigit{3}}{\isacharparenright}\ a\ as\ x\ xs\ \isakeyword{where}\ {\isachardoublequoteopen}ps\ {\isacharequal}\ a{\isacharhash}as{\isachardoublequoteclose}\ \isakeyword{and}\ {\isachardoublequoteopen}ls\ {\isacharequal}\ x{\isacharhash}xs{\isachardoublequoteclose}\ \isakeyword{and}\ {\isachardoublequoteopen}x\ {\isasymnoteq}\ a{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+\ {\isacharparenleft}cases\ ps{\isacharparenright}\isanewline
+\ \ \isacommand{case}\isamarkupfalse%
+\ Nil\ \isacommand{then}\isamarkupfalse%
+\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{using}\isamarkupfalse%
+\ pfx\ \isacommand{by}\isamarkupfalse%
+\ simp\isanewline
+\isacommand{next}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{case}\isamarkupfalse%
+\ {\isacharparenleft}Cons\ a\ as{\isacharparenright}\isanewline
+\ \ \isacommand{note}\isamarkupfalse%
+\ c\ {\isacharequal}\ {\isacharbackquoteopen}ps\ {\isacharequal}\ a{\isacharhash}as{\isacharbackquoteclose}\isanewline
+\ \ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\isanewline
+\ \ \isacommand{proof}\isamarkupfalse%
+\ {\isacharparenleft}cases\ ls{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{case}\isamarkupfalse%
+\ Nil\ \isacommand{then}\isamarkupfalse%
+\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}metis\ append{\isacharunderscore}Nil{\isadigit{2}}\ pfx\ c{\isadigit{1}}\ same{\isacharunderscore}prefix{\isacharunderscore}nil{\isacharparenright}\isanewline
+\ \ \isacommand{next}\isamarkupfalse%
+\isanewline
+\ \ \ \ \isacommand{case}\isamarkupfalse%
+\ {\isacharparenleft}Cons\ x\ xs{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\isanewline
+\ \ \ \ \isacommand{proof}\isamarkupfalse%
+\ {\isacharparenleft}cases\ {\isachardoublequoteopen}x\ {\isacharequal}\ a{\isachardoublequoteclose}{\isacharparenright}\isanewline
+\ \ \ \ \ \ \isacommand{case}\isamarkupfalse%
+\ True\isanewline
+\ \ \ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isasymnot}\ as\ {\isasymle}\ xs{\isachardoublequoteclose}\ \isacommand{using}\isamarkupfalse%
+\ pfx\ c\ Cons\ True\ \isacommand{by}\isamarkupfalse%
+\ simp\isanewline
+\ \ \ \ \ \ \isacommand{with}\isamarkupfalse%
+\ c\ Cons\ True\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}rule\ c{\isadigit{2}}{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{next}\isamarkupfalse%
+\isanewline
+\ \ \ \ \ \ \isacommand{case}\isamarkupfalse%
+\ False\isanewline
+\ \ \ \ \ \ \isacommand{with}\isamarkupfalse%
+\ c\ Cons\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}rule\ c{\isadigit{3}}{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ not{\isacharunderscore}prefix{\isacharunderscore}induct\ {\isacharbrackleft}consumes\ {\isadigit{1}}{\isacharcomma}\ case{\isacharunderscore}names\ Nil\ Neq\ Eq{\isacharbrackright}{\isacharcolon}\isanewline
+\ \ \isakeyword{assumes}\ np{\isacharcolon}\ {\isachardoublequoteopen}{\isasymnot}\ ps\ {\isasymle}\ ls{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isakeyword{and}\ base{\isacharcolon}\ {\isachardoublequoteopen}{\isasymAnd}x\ xs{\isachardot}\ P\ {\isacharparenleft}x{\isacharhash}xs{\isacharparenright}\ {\isacharbrackleft}{\isacharbrackright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isakeyword{and}\ r{\isadigit{1}}{\isacharcolon}\ {\isachardoublequoteopen}{\isasymAnd}x\ xs\ y\ ys{\isachardot}\ x\ {\isasymnoteq}\ y\ {\isasymLongrightarrow}\ P\ {\isacharparenleft}x{\isacharhash}xs{\isacharparenright}\ {\isacharparenleft}y{\isacharhash}ys{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isakeyword{and}\ r{\isadigit{2}}{\isacharcolon}\ {\isachardoublequoteopen}{\isasymAnd}x\ xs\ y\ ys{\isachardot}\ {\isasymlbrakk}\ x\ {\isacharequal}\ y{\isacharsemicolon}\ {\isasymnot}\ xs\ {\isasymle}\ ys{\isacharsemicolon}\ P\ xs\ ys\ {\isasymrbrakk}\ {\isasymLongrightarrow}\ P\ {\isacharparenleft}x{\isacharhash}xs{\isacharparenright}\ {\isacharparenleft}y{\isacharhash}ys{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{shows}\ {\isachardoublequoteopen}P\ ps\ ls{\isachardoublequoteclose}%
+\isadelimproof
+\ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{using}\isamarkupfalse%
+\ np\isanewline
+\isacommand{proof}\isamarkupfalse%
+\ {\isacharparenleft}induct\ ls\ arbitrary{\isacharcolon}\ ps{\isacharparenright}\isanewline
+\ \ \isacommand{case}\isamarkupfalse%
+\ Nil\ \isacommand{then}\isamarkupfalse%
+\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}case\isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}\ neq{\isacharunderscore}Nil{\isacharunderscore}conv\ elim{\isacharbang}{\isacharcolon}\ not{\isacharunderscore}prefix{\isacharunderscore}cases\ intro{\isacharbang}{\isacharcolon}\ base{\isacharparenright}\isanewline
+\isacommand{next}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{case}\isamarkupfalse%
+\ {\isacharparenleft}Cons\ y\ ys{\isacharparenright}\isanewline
+\ \ \isacommand{then}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ npfx{\isacharcolon}\ {\isachardoublequoteopen}{\isasymnot}\ ps\ {\isasymle}\ {\isacharparenleft}y\ {\isacharhash}\ ys{\isacharparenright}{\isachardoublequoteclose}\ \isacommand{by}\isamarkupfalse%
+\ simp\isanewline
+\ \ \isacommand{then}\isamarkupfalse%
+\ \isacommand{obtain}\isamarkupfalse%
+\ x\ xs\ \isakeyword{where}\ pv{\isacharcolon}\ {\isachardoublequoteopen}ps\ {\isacharequal}\ x\ {\isacharhash}\ xs{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}rule\ not{\isacharunderscore}prefix{\isacharunderscore}cases{\isacharparenright}\ auto\isanewline
+\ \ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}case\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}metis\ Cons{\isachardot}hyps\ Cons{\isacharunderscore}prefix{\isacharunderscore}Cons\ npfx\ pv\ r{\isadigit{1}}\ r{\isadigit{2}}{\isacharparenright}\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isamarkupsubsection{Parallel lists%
+}
+\isamarkuptrue%
+\isacommand{definition}\isamarkupfalse%
+\isanewline
+\ \ parallel\ {\isacharcolon}{\isacharcolon}\ {\isachardoublequoteopen}{\isacharprime}a\ list\ {\isacharequal}{\isachargreater}\ {\isacharprime}a\ list\ {\isacharequal}{\isachargreater}\ bool{\isachardoublequoteclose}\ \ {\isacharparenleft}\isakeyword{infixl}\ {\isachardoublequoteopen}{\isasymparallel}{\isachardoublequoteclose}\ {\isadigit{5}}{\isadigit{0}}{\isacharparenright}\ \isakeyword{where}\isanewline
+\ \ {\isachardoublequoteopen}{\isacharparenleft}xs\ {\isasymparallel}\ ys{\isacharparenright}\ {\isacharequal}\ {\isacharparenleft}{\isasymnot}\ xs\ {\isasymle}\ ys\ {\isasymand}\ {\isasymnot}\ ys\ {\isasymle}\ xs{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ parallelI\ {\isacharbrackleft}intro{\isacharbrackright}{\isacharcolon}\ {\isachardoublequoteopen}{\isasymnot}\ xs\ {\isasymle}\ ys\ {\isacharequal}{\isacharequal}{\isachargreater}\ {\isasymnot}\ ys\ {\isasymle}\ xs\ {\isacharequal}{\isacharequal}{\isachargreater}\ xs\ {\isasymparallel}\ ys{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{unfolding}\isamarkupfalse%
+\ parallel{\isacharunderscore}def\ \isacommand{by}\isamarkupfalse%
+\ blast%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ parallelE\ {\isacharbrackleft}elim{\isacharbrackright}{\isacharcolon}\isanewline
+\ \ \isakeyword{assumes}\ {\isachardoublequoteopen}xs\ {\isasymparallel}\ ys{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{obtains}\ {\isachardoublequoteopen}{\isasymnot}\ xs\ {\isasymle}\ ys\ {\isasymand}\ {\isasymnot}\ ys\ {\isasymle}\ xs{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{using}\isamarkupfalse%
+\ assms\ \isacommand{unfolding}\isamarkupfalse%
+\ parallel{\isacharunderscore}def\ \isacommand{by}\isamarkupfalse%
+\ blast%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{theorem}\isamarkupfalse%
+\ prefix{\isacharunderscore}cases{\isacharcolon}\isanewline
+\ \ \isakeyword{obtains}\ {\isachardoublequoteopen}xs\ {\isasymle}\ ys{\isachardoublequoteclose}\ {\isacharbar}\ {\isachardoublequoteopen}ys\ {\isacharless}\ xs{\isachardoublequoteclose}\ {\isacharbar}\ {\isachardoublequoteopen}xs\ {\isasymparallel}\ ys{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{unfolding}\isamarkupfalse%
+\ parallel{\isacharunderscore}def\ strict{\isacharunderscore}prefix{\isacharunderscore}def\ \isacommand{by}\isamarkupfalse%
+\ blast%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{theorem}\isamarkupfalse%
+\ parallel{\isacharunderscore}decomp{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}xs\ {\isasymparallel}\ ys\ {\isacharequal}{\isacharequal}{\isachargreater}\ {\isasymexists}as\ b\ bs\ c\ cs{\isachardot}\ b\ {\isasymnoteq}\ c\ {\isasymand}\ xs\ {\isacharequal}\ as\ {\isacharat}\ b\ {\isacharhash}\ bs\ {\isasymand}\ ys\ {\isacharequal}\ as\ {\isacharat}\ c\ {\isacharhash}\ cs{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+\ {\isacharparenleft}induct\ xs\ rule{\isacharcolon}\ rev{\isacharunderscore}induct{\isacharparenright}\isanewline
+\ \ \isacommand{case}\isamarkupfalse%
+\ Nil\isanewline
+\ \ \isacommand{then}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ False\ \isacommand{by}\isamarkupfalse%
+\ auto\isanewline
+\ \ \isacommand{then}\isamarkupfalse%
+\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}case\ \isacommand{{\isachardot}{\isachardot}}\isamarkupfalse%
+\isanewline
+\isacommand{next}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{case}\isamarkupfalse%
+\ {\isacharparenleft}snoc\ x\ xs{\isacharparenright}\isanewline
+\ \ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}case\isanewline
+\ \ \isacommand{proof}\isamarkupfalse%
+\ {\isacharparenleft}rule\ prefix{\isacharunderscore}cases{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{assume}\isamarkupfalse%
+\ le{\isacharcolon}\ {\isachardoublequoteopen}xs\ {\isasymle}\ ys{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{then}\isamarkupfalse%
+\ \isacommand{obtain}\isamarkupfalse%
+\ ys{\isacharprime}\ \isakeyword{where}\ ys{\isacharcolon}\ {\isachardoublequoteopen}ys\ {\isacharequal}\ xs\ {\isacharat}\ ys{\isacharprime}{\isachardoublequoteclose}\ \isacommand{{\isachardot}{\isachardot}}\isamarkupfalse%
+\isanewline
+\ \ \ \ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\isanewline
+\ \ \ \ \isacommand{proof}\isamarkupfalse%
+\ {\isacharparenleft}cases\ ys{\isacharprime}{\isacharparenright}\isanewline
+\ \ \ \ \ \ \isacommand{assume}\isamarkupfalse%
+\ {\isachardoublequoteopen}ys{\isacharprime}\ {\isacharequal}\ {\isacharbrackleft}{\isacharbrackright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \isacommand{then}\isamarkupfalse%
+\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}metis\ append{\isacharunderscore}Nil{\isadigit{2}}\ parallelE\ prefixI\ snoc{\isachardot}prems\ ys{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{next}\isamarkupfalse%
+\isanewline
+\ \ \ \ \ \ \isacommand{fix}\isamarkupfalse%
+\ c\ cs\ \isacommand{assume}\isamarkupfalse%
+\ ys{\isacharprime}{\isacharcolon}\ {\isachardoublequoteopen}ys{\isacharprime}\ {\isacharequal}\ c\ {\isacharhash}\ cs{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \isacommand{then}\isamarkupfalse%
+\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\isanewline
+\ \ \ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}metis\ Cons{\isacharunderscore}eq{\isacharunderscore}appendI\ eq{\isacharunderscore}Nil{\isacharunderscore}appendI\ parallelE\ prefixI\isanewline
+\ \ \ \ \ \ \ \ \ \ same{\isacharunderscore}prefix{\isacharunderscore}prefix\ snoc{\isachardot}prems\ ys{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{next}\isamarkupfalse%
+\isanewline
+\ \ \ \ \isacommand{assume}\isamarkupfalse%
+\ {\isachardoublequoteopen}ys\ {\isacharless}\ xs{\isachardoublequoteclose}\ \isacommand{then}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}ys\ {\isasymle}\ xs\ {\isacharat}\ {\isacharbrackleft}x{\isacharbrackright}{\isachardoublequoteclose}\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}simp\ add{\isacharcolon}\ strict{\isacharunderscore}prefix{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{with}\isamarkupfalse%
+\ snoc\ \isacommand{have}\isamarkupfalse%
+\ False\ \isacommand{by}\isamarkupfalse%
+\ blast\isanewline
+\ \ \ \ \isacommand{then}\isamarkupfalse%
+\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{{\isachardot}{\isachardot}}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{next}\isamarkupfalse%
+\isanewline
+\ \ \ \ \isacommand{assume}\isamarkupfalse%
+\ {\isachardoublequoteopen}xs\ {\isasymparallel}\ ys{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{with}\isamarkupfalse%
+\ snoc\ \isacommand{obtain}\isamarkupfalse%
+\ as\ b\ bs\ c\ cs\ \isakeyword{where}\ neq{\isacharcolon}\ {\isachardoublequoteopen}{\isacharparenleft}b{\isacharcolon}{\isacharcolon}{\isacharprime}a{\isacharparenright}\ {\isasymnoteq}\ c{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \isakeyword{and}\ xs{\isacharcolon}\ {\isachardoublequoteopen}xs\ {\isacharequal}\ as\ {\isacharat}\ b\ {\isacharhash}\ bs{\isachardoublequoteclose}\ \isakeyword{and}\ ys{\isacharcolon}\ {\isachardoublequoteopen}ys\ {\isacharequal}\ as\ {\isacharat}\ c\ {\isacharhash}\ cs{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ blast\isanewline
+\ \ \ \ \isacommand{from}\isamarkupfalse%
+\ xs\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}xs\ {\isacharat}\ {\isacharbrackleft}x{\isacharbrackright}\ {\isacharequal}\ as\ {\isacharat}\ b\ {\isacharhash}\ {\isacharparenleft}bs\ {\isacharat}\ {\isacharbrackleft}x{\isacharbrackright}{\isacharparenright}{\isachardoublequoteclose}\ \isacommand{by}\isamarkupfalse%
+\ simp\isanewline
+\ \ \ \ \isacommand{with}\isamarkupfalse%
+\ neq\ ys\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ blast\isanewline
+\ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ parallel{\isacharunderscore}append{\isacharcolon}\ {\isachardoublequoteopen}a\ {\isasymparallel}\ b\ {\isasymLongrightarrow}\ a\ {\isacharat}\ c\ {\isasymparallel}\ b\ {\isacharat}\ d{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}rule\ parallelI{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}erule\ parallelE{\isacharcomma}\ erule\ conjE{\isacharcomma}\isanewline
+\ \ \ \ \ \ induct\ rule{\isacharcolon}\ not{\isacharunderscore}prefix{\isacharunderscore}induct{\isacharcomma}\ simp{\isacharplus}{\isacharparenright}{\isacharplus}\isanewline
+\ \ \isacommand{done}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ parallel{\isacharunderscore}appendI{\isacharcolon}\ {\isachardoublequoteopen}xs\ {\isasymparallel}\ ys\ {\isasymLongrightarrow}\ x\ {\isacharequal}\ xs\ {\isacharat}\ xs{\isacharprime}\ {\isasymLongrightarrow}\ y\ {\isacharequal}\ ys\ {\isacharat}\ ys{\isacharprime}\ {\isasymLongrightarrow}\ x\ {\isasymparallel}\ y{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}simp\ add{\isacharcolon}\ parallel{\isacharunderscore}append{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ parallel{\isacharunderscore}commute{\isacharcolon}\ {\isachardoublequoteopen}a\ {\isasymparallel}\ b\ {\isasymlongleftrightarrow}\ b\ {\isasymparallel}\ a{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{unfolding}\isamarkupfalse%
+\ parallel{\isacharunderscore}def\ \isacommand{by}\isamarkupfalse%
+\ auto%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isamarkupsubsection{Postfix order on lists%
+}
+\isamarkuptrue%
+\isacommand{definition}\isamarkupfalse%
+\isanewline
+\ \ postfix\ {\isacharcolon}{\isacharcolon}\ {\isachardoublequoteopen}{\isacharprime}a\ list\ {\isacharequal}{\isachargreater}\ {\isacharprime}a\ list\ {\isacharequal}{\isachargreater}\ bool{\isachardoublequoteclose}\ \ {\isacharparenleft}{\isachardoublequoteopen}{\isacharparenleft}{\isacharunderscore}{\isacharslash}\ {\isachargreater}{\isachargreater}{\isacharequal}\ {\isacharunderscore}{\isacharparenright}{\isachardoublequoteclose}\ {\isacharbrackleft}{\isadigit{5}}{\isadigit{1}}{\isacharcomma}\ {\isadigit{5}}{\isadigit{0}}{\isacharbrackright}\ {\isadigit{5}}{\isadigit{0}}{\isacharparenright}\ \isakeyword{where}\isanewline
+\ \ {\isachardoublequoteopen}{\isacharparenleft}xs\ {\isachargreater}{\isachargreater}{\isacharequal}\ ys{\isacharparenright}\ {\isacharequal}\ {\isacharparenleft}{\isasymexists}zs{\isachardot}\ xs\ {\isacharequal}\ zs\ {\isacharat}\ ys{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ postfixI\ {\isacharbrackleft}intro{\isacharquery}{\isacharbrackright}{\isacharcolon}\ {\isachardoublequoteopen}xs\ {\isacharequal}\ zs\ {\isacharat}\ ys\ {\isacharequal}{\isacharequal}{\isachargreater}\ xs\ {\isachargreater}{\isachargreater}{\isacharequal}\ ys{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{unfolding}\isamarkupfalse%
+\ postfix{\isacharunderscore}def\ \isacommand{by}\isamarkupfalse%
+\ blast%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ postfixE\ {\isacharbrackleft}elim{\isacharquery}{\isacharbrackright}{\isacharcolon}\isanewline
+\ \ \isakeyword{assumes}\ {\isachardoublequoteopen}xs\ {\isachargreater}{\isachargreater}{\isacharequal}\ ys{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{obtains}\ zs\ \isakeyword{where}\ {\isachardoublequoteopen}xs\ {\isacharequal}\ zs\ {\isacharat}\ ys{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{using}\isamarkupfalse%
+\ assms\ \isacommand{unfolding}\isamarkupfalse%
+\ postfix{\isacharunderscore}def\ \isacommand{by}\isamarkupfalse%
+\ blast%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ postfix{\isacharunderscore}refl\ {\isacharbrackleft}iff{\isacharbrackright}{\isacharcolon}\ {\isachardoublequoteopen}xs\ {\isachargreater}{\isachargreater}{\isacharequal}\ xs{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp\ add{\isacharcolon}\ postfix{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isacommand{lemma}\isamarkupfalse%
+\ postfix{\isacharunderscore}trans{\isacharcolon}\ {\isachardoublequoteopen}{\isasymlbrakk}xs\ {\isachargreater}{\isachargreater}{\isacharequal}\ ys{\isacharsemicolon}\ ys\ {\isachargreater}{\isachargreater}{\isacharequal}\ zs{\isasymrbrakk}\ {\isasymLongrightarrow}\ xs\ {\isachargreater}{\isachargreater}{\isacharequal}\ zs{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp\ add{\isacharcolon}\ postfix{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isacommand{lemma}\isamarkupfalse%
+\ postfix{\isacharunderscore}antisym{\isacharcolon}\ {\isachardoublequoteopen}{\isasymlbrakk}xs\ {\isachargreater}{\isachargreater}{\isacharequal}\ ys{\isacharsemicolon}\ ys\ {\isachargreater}{\isachargreater}{\isacharequal}\ xs{\isasymrbrakk}\ {\isasymLongrightarrow}\ xs\ {\isacharequal}\ ys{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp\ add{\isacharcolon}\ postfix{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ Nil{\isacharunderscore}postfix\ {\isacharbrackleft}iff{\isacharbrackright}{\isacharcolon}\ {\isachardoublequoteopen}xs\ {\isachargreater}{\isachargreater}{\isacharequal}\ {\isacharbrackleft}{\isacharbrackright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}simp\ add{\isacharcolon}\ postfix{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isacommand{lemma}\isamarkupfalse%
+\ postfix{\isacharunderscore}Nil\ {\isacharbrackleft}simp{\isacharbrackright}{\isacharcolon}\ {\isachardoublequoteopen}{\isacharparenleft}{\isacharbrackleft}{\isacharbrackright}\ {\isachargreater}{\isachargreater}{\isacharequal}\ xs{\isacharparenright}\ {\isacharequal}\ {\isacharparenleft}xs\ {\isacharequal}\ {\isacharbrackleft}{\isacharbrackright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp\ add{\isacharcolon}\ postfix{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ postfix{\isacharunderscore}ConsI{\isacharcolon}\ {\isachardoublequoteopen}xs\ {\isachargreater}{\isachargreater}{\isacharequal}\ ys\ {\isasymLongrightarrow}\ x{\isacharhash}xs\ {\isachargreater}{\isachargreater}{\isacharequal}\ ys{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp\ add{\isacharcolon}\ postfix{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isacommand{lemma}\isamarkupfalse%
+\ postfix{\isacharunderscore}ConsD{\isacharcolon}\ {\isachardoublequoteopen}xs\ {\isachargreater}{\isachargreater}{\isacharequal}\ y{\isacharhash}ys\ {\isasymLongrightarrow}\ xs\ {\isachargreater}{\isachargreater}{\isacharequal}\ ys{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp\ add{\isacharcolon}\ postfix{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ postfix{\isacharunderscore}appendI{\isacharcolon}\ {\isachardoublequoteopen}xs\ {\isachargreater}{\isachargreater}{\isacharequal}\ ys\ {\isasymLongrightarrow}\ zs\ {\isacharat}\ xs\ {\isachargreater}{\isachargreater}{\isacharequal}\ ys{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp\ add{\isacharcolon}\ postfix{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isacommand{lemma}\isamarkupfalse%
+\ postfix{\isacharunderscore}appendD{\isacharcolon}\ {\isachardoublequoteopen}xs\ {\isachargreater}{\isachargreater}{\isacharequal}\ zs\ {\isacharat}\ ys\ {\isasymLongrightarrow}\ xs\ {\isachargreater}{\isachargreater}{\isacharequal}\ ys{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp\ add{\isacharcolon}\ postfix{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ postfix{\isacharunderscore}is{\isacharunderscore}subset{\isacharcolon}\ {\isachardoublequoteopen}xs\ {\isachargreater}{\isachargreater}{\isacharequal}\ ys\ {\isacharequal}{\isacharequal}{\isachargreater}\ set\ ys\ {\isasymsubseteq}\ set\ xs{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+\ {\isacharminus}\isanewline
+\ \ \isacommand{assume}\isamarkupfalse%
+\ {\isachardoublequoteopen}xs\ {\isachargreater}{\isachargreater}{\isacharequal}\ ys{\isachardoublequoteclose}\isanewline
+\ \ \isacommand{then}\isamarkupfalse%
+\ \isacommand{obtain}\isamarkupfalse%
+\ zs\ \isakeyword{where}\ {\isachardoublequoteopen}xs\ {\isacharequal}\ zs\ {\isacharat}\ ys{\isachardoublequoteclose}\ \isacommand{{\isachardot}{\isachardot}}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{then}\isamarkupfalse%
+\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}induct\ zs{\isacharparenright}\ auto\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ postfix{\isacharunderscore}ConsD{\isadigit{2}}{\isacharcolon}\ {\isachardoublequoteopen}x{\isacharhash}xs\ {\isachargreater}{\isachargreater}{\isacharequal}\ y{\isacharhash}ys\ {\isacharequal}{\isacharequal}{\isachargreater}\ xs\ {\isachargreater}{\isachargreater}{\isacharequal}\ ys{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+\ {\isacharminus}\isanewline
+\ \ \isacommand{assume}\isamarkupfalse%
+\ {\isachardoublequoteopen}x{\isacharhash}xs\ {\isachargreater}{\isachargreater}{\isacharequal}\ y{\isacharhash}ys{\isachardoublequoteclose}\isanewline
+\ \ \isacommand{then}\isamarkupfalse%
+\ \isacommand{obtain}\isamarkupfalse%
+\ zs\ \isakeyword{where}\ {\isachardoublequoteopen}x{\isacharhash}xs\ {\isacharequal}\ zs\ {\isacharat}\ y{\isacharhash}ys{\isachardoublequoteclose}\ \isacommand{{\isachardot}{\isachardot}}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{then}\isamarkupfalse%
+\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}induct\ zs{\isacharparenright}\ {\isacharparenleft}auto\ intro{\isacharbang}{\isacharcolon}\ postfix{\isacharunderscore}appendI\ postfix{\isacharunderscore}ConsI{\isacharparenright}\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ postfix{\isacharunderscore}to{\isacharunderscore}prefix{\isacharcolon}\ {\isachardoublequoteopen}xs\ {\isachargreater}{\isachargreater}{\isacharequal}\ ys\ {\isasymlongleftrightarrow}\ rev\ ys\ {\isasymle}\ rev\ xs{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{assume}\isamarkupfalse%
+\ {\isachardoublequoteopen}xs\ {\isachargreater}{\isachargreater}{\isacharequal}\ ys{\isachardoublequoteclose}\isanewline
+\ \ \isacommand{then}\isamarkupfalse%
+\ \isacommand{obtain}\isamarkupfalse%
+\ zs\ \isakeyword{where}\ {\isachardoublequoteopen}xs\ {\isacharequal}\ zs\ {\isacharat}\ ys{\isachardoublequoteclose}\ \isacommand{{\isachardot}{\isachardot}}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{then}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}rev\ xs\ {\isacharequal}\ rev\ ys\ {\isacharat}\ rev\ zs{\isachardoublequoteclose}\ \isacommand{by}\isamarkupfalse%
+\ simp\isanewline
+\ \ \isacommand{then}\isamarkupfalse%
+\ \isacommand{show}\isamarkupfalse%
+\ {\isachardoublequoteopen}rev\ ys\ {\isacharless}{\isacharequal}\ rev\ xs{\isachardoublequoteclose}\ \isacommand{{\isachardot}{\isachardot}}\isamarkupfalse%
+\isanewline
+\isacommand{next}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{assume}\isamarkupfalse%
+\ {\isachardoublequoteopen}rev\ ys\ {\isacharless}{\isacharequal}\ rev\ xs{\isachardoublequoteclose}\isanewline
+\ \ \isacommand{then}\isamarkupfalse%
+\ \isacommand{obtain}\isamarkupfalse%
+\ zs\ \isakeyword{where}\ {\isachardoublequoteopen}rev\ xs\ {\isacharequal}\ rev\ ys\ {\isacharat}\ zs{\isachardoublequoteclose}\ \isacommand{{\isachardot}{\isachardot}}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{then}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}rev\ {\isacharparenleft}rev\ xs{\isacharparenright}\ {\isacharequal}\ rev\ zs\ {\isacharat}\ rev\ {\isacharparenleft}rev\ ys{\isacharparenright}{\isachardoublequoteclose}\ \isacommand{by}\isamarkupfalse%
+\ simp\isanewline
+\ \ \isacommand{then}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}xs\ {\isacharequal}\ rev\ zs\ {\isacharat}\ ys{\isachardoublequoteclose}\ \isacommand{by}\isamarkupfalse%
+\ simp\isanewline
+\ \ \isacommand{then}\isamarkupfalse%
+\ \isacommand{show}\isamarkupfalse%
+\ {\isachardoublequoteopen}xs\ {\isachargreater}{\isachargreater}{\isacharequal}\ ys{\isachardoublequoteclose}\ \isacommand{{\isachardot}{\isachardot}}\isamarkupfalse%
+\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ distinct{\isacharunderscore}postfix{\isacharcolon}\ {\isachardoublequoteopen}distinct\ xs\ {\isasymLongrightarrow}\ xs\ {\isachargreater}{\isachargreater}{\isacharequal}\ ys\ {\isasymLongrightarrow}\ distinct\ ys{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}clarsimp\ elim{\isacharbang}{\isacharcolon}\ postfixE{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ postfix{\isacharunderscore}map{\isacharcolon}\ {\isachardoublequoteopen}xs\ {\isachargreater}{\isachargreater}{\isacharequal}\ ys\ {\isasymLongrightarrow}\ map\ f\ xs\ {\isachargreater}{\isachargreater}{\isacharequal}\ map\ f\ ys{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ elim{\isacharbang}{\isacharcolon}\ postfixE\ intro{\isacharcolon}\ postfixI{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ postfix{\isacharunderscore}drop{\isacharcolon}\ {\isachardoublequoteopen}as\ {\isachargreater}{\isachargreater}{\isacharequal}\ drop\ n\ as{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{unfolding}\isamarkupfalse%
+\ postfix{\isacharunderscore}def\isanewline
+\ \ \isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}rule\ exI\ {\isacharbrackleft}\isakeyword{where}\ x\ {\isacharequal}\ {\isachardoublequoteopen}take\ n\ as{\isachardoublequoteclose}{\isacharbrackright}{\isacharparenright}\isanewline
+\ \ \isacommand{apply}\isamarkupfalse%
+\ simp\isanewline
+\ \ \isacommand{done}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ postfix{\isacharunderscore}take{\isacharcolon}\ {\isachardoublequoteopen}xs\ {\isachargreater}{\isachargreater}{\isacharequal}\ ys\ {\isasymLongrightarrow}\ xs\ {\isacharequal}\ take\ {\isacharparenleft}length\ xs\ {\isacharminus}\ length\ ys{\isacharparenright}\ xs\ {\isacharat}\ ys{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}clarsimp\ elim{\isacharbang}{\isacharcolon}\ postfixE{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ parallelD{\isadigit{1}}{\isacharcolon}\ {\isachardoublequoteopen}x\ {\isasymparallel}\ y\ {\isasymLongrightarrow}\ {\isasymnot}\ x\ {\isasymle}\ y{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ blast%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ parallelD{\isadigit{2}}{\isacharcolon}\ {\isachardoublequoteopen}x\ {\isasymparallel}\ y\ {\isasymLongrightarrow}\ {\isasymnot}\ y\ {\isasymle}\ x{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ blast%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ parallel{\isacharunderscore}Nil{\isadigit{1}}\ {\isacharbrackleft}simp{\isacharbrackright}{\isacharcolon}\ {\isachardoublequoteopen}{\isasymnot}\ x\ {\isasymparallel}\ {\isacharbrackleft}{\isacharbrackright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{unfolding}\isamarkupfalse%
+\ parallel{\isacharunderscore}def\ \isacommand{by}\isamarkupfalse%
+\ simp%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ parallel{\isacharunderscore}Nil{\isadigit{2}}\ {\isacharbrackleft}simp{\isacharbrackright}{\isacharcolon}\ {\isachardoublequoteopen}{\isasymnot}\ {\isacharbrackleft}{\isacharbrackright}\ {\isasymparallel}\ x{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{unfolding}\isamarkupfalse%
+\ parallel{\isacharunderscore}def\ \isacommand{by}\isamarkupfalse%
+\ simp%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ Cons{\isacharunderscore}parallelI{\isadigit{1}}{\isacharcolon}\ {\isachardoublequoteopen}a\ {\isasymnoteq}\ b\ {\isasymLongrightarrow}\ a\ {\isacharhash}\ as\ {\isasymparallel}\ b\ {\isacharhash}\ bs{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ auto%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ Cons{\isacharunderscore}parallelI{\isadigit{2}}{\isacharcolon}\ {\isachardoublequoteopen}{\isasymlbrakk}\ a\ {\isacharequal}\ b{\isacharsemicolon}\ as\ {\isasymparallel}\ bs\ {\isasymrbrakk}\ {\isasymLongrightarrow}\ a\ {\isacharhash}\ as\ {\isasymparallel}\ b\ {\isacharhash}\ bs{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}metis\ Cons{\isacharunderscore}prefix{\isacharunderscore}Cons\ parallelE\ parallelI{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ not{\isacharunderscore}equal{\isacharunderscore}is{\isacharunderscore}parallel{\isacharcolon}\isanewline
+\ \ \isakeyword{assumes}\ neq{\isacharcolon}\ {\isachardoublequoteopen}xs\ {\isasymnoteq}\ ys{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isakeyword{and}\ len{\isacharcolon}\ {\isachardoublequoteopen}length\ xs\ {\isacharequal}\ length\ ys{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{shows}\ {\isachardoublequoteopen}xs\ {\isasymparallel}\ ys{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{using}\isamarkupfalse%
+\ len\ neq\isanewline
+\isacommand{proof}\isamarkupfalse%
+\ {\isacharparenleft}induct\ rule{\isacharcolon}\ list{\isacharunderscore}induct{\isadigit{2}}{\isacharparenright}\isanewline
+\ \ \isacommand{case}\isamarkupfalse%
+\ Nil\isanewline
+\ \ \isacommand{then}\isamarkupfalse%
+\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}case\ \isacommand{by}\isamarkupfalse%
+\ simp\isanewline
+\isacommand{next}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{case}\isamarkupfalse%
+\ {\isacharparenleft}Cons\ a\ as\ b\ bs{\isacharparenright}\isanewline
+\ \ \isacommand{have}\isamarkupfalse%
+\ ih{\isacharcolon}\ {\isachardoublequoteopen}as\ {\isasymnoteq}\ bs\ {\isasymLongrightarrow}\ as\ {\isasymparallel}\ bs{\isachardoublequoteclose}\ \isacommand{by}\isamarkupfalse%
+\ fact\isanewline
+\ \ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}case\isanewline
+\ \ \isacommand{proof}\isamarkupfalse%
+\ {\isacharparenleft}cases\ {\isachardoublequoteopen}a\ {\isacharequal}\ b{\isachardoublequoteclose}{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{case}\isamarkupfalse%
+\ True\isanewline
+\ \ \ \ \isacommand{then}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}as\ {\isasymnoteq}\ bs{\isachardoublequoteclose}\ \isacommand{using}\isamarkupfalse%
+\ Cons\ \isacommand{by}\isamarkupfalse%
+\ simp\isanewline
+\ \ \ \ \isacommand{then}\isamarkupfalse%
+\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}rule\ Cons{\isacharunderscore}parallelI{\isadigit{2}}\ {\isacharbrackleft}OF\ True\ ih{\isacharbrackright}{\isacharparenright}\isanewline
+\ \ \isacommand{next}\isamarkupfalse%
+\isanewline
+\ \ \ \ \isacommand{case}\isamarkupfalse%
+\ False\isanewline
+\ \ \ \ \isacommand{then}\isamarkupfalse%
+\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}rule\ Cons{\isacharunderscore}parallelI{\isadigit{1}}{\isacharparenright}\isanewline
+\ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isamarkupsubsection{Executable code%
+}
+\isamarkuptrue%
+\isacommand{lemma}\isamarkupfalse%
+\ less{\isacharunderscore}eq{\isacharunderscore}code\ {\isacharbrackleft}code{\isacharbrackright}{\isacharcolon}\isanewline
+\ \ \ \ {\isachardoublequoteopen}{\isacharparenleft}{\isacharbrackleft}{\isacharbrackright}{\isasymColon}{\isacharprime}a{\isasymColon}{\isacharbraceleft}eq{\isacharcomma}\ ord{\isacharbraceright}\ list{\isacharparenright}\ {\isasymle}\ xs\ {\isasymlongleftrightarrow}\ True{\isachardoublequoteclose}\isanewline
+\ \ \ \ {\isachardoublequoteopen}{\isacharparenleft}x{\isasymColon}{\isacharprime}a{\isasymColon}{\isacharbraceleft}eq{\isacharcomma}\ ord{\isacharbraceright}{\isacharparenright}\ {\isacharhash}\ xs\ {\isasymle}\ {\isacharbrackleft}{\isacharbrackright}\ {\isasymlongleftrightarrow}\ False{\isachardoublequoteclose}\isanewline
+\ \ \ \ {\isachardoublequoteopen}{\isacharparenleft}x{\isasymColon}{\isacharprime}a{\isasymColon}{\isacharbraceleft}eq{\isacharcomma}\ ord{\isacharbraceright}{\isacharparenright}\ {\isacharhash}\ xs\ {\isasymle}\ y\ {\isacharhash}\ ys\ {\isasymlongleftrightarrow}\ x\ {\isacharequal}\ y\ {\isasymand}\ xs\ {\isasymle}\ ys{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ simp{\isacharunderscore}all%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ less{\isacharunderscore}code\ {\isacharbrackleft}code{\isacharbrackright}{\isacharcolon}\isanewline
+\ \ \ \ {\isachardoublequoteopen}xs\ {\isacharless}\ {\isacharparenleft}{\isacharbrackleft}{\isacharbrackright}{\isasymColon}{\isacharprime}a{\isasymColon}{\isacharbraceleft}eq{\isacharcomma}\ ord{\isacharbraceright}\ list{\isacharparenright}\ {\isasymlongleftrightarrow}\ False{\isachardoublequoteclose}\isanewline
+\ \ \ \ {\isachardoublequoteopen}{\isacharbrackleft}{\isacharbrackright}\ {\isacharless}\ {\isacharparenleft}x{\isasymColon}{\isacharprime}a{\isasymColon}{\isacharbraceleft}eq{\isacharcomma}\ ord{\isacharbraceright}{\isacharparenright}{\isacharhash}\ xs\ {\isasymlongleftrightarrow}\ True{\isachardoublequoteclose}\isanewline
+\ \ \ \ {\isachardoublequoteopen}{\isacharparenleft}x{\isasymColon}{\isacharprime}a{\isasymColon}{\isacharbraceleft}eq{\isacharcomma}\ ord{\isacharbraceright}{\isacharparenright}\ {\isacharhash}\ xs\ {\isacharless}\ y\ {\isacharhash}\ ys\ {\isasymlongleftrightarrow}\ x\ {\isacharequal}\ y\ {\isasymand}\ xs\ {\isacharless}\ ys{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{unfolding}\isamarkupfalse%
+\ strict{\isacharunderscore}prefix{\isacharunderscore}def\ \isacommand{by}\isamarkupfalse%
+\ auto%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemmas}\isamarkupfalse%
+\ {\isacharbrackleft}code{\isacharbrackright}\ {\isacharequal}\ postfix{\isacharunderscore}to{\isacharunderscore}prefix\isanewline
+%
+\isadelimtheory
+\isanewline
+%
+\endisadelimtheory
+%
+\isatagtheory
+\isacommand{end}\isamarkupfalse%
+%
+\endisatagtheory
+{\isafoldtheory}%
+%
+\isadelimtheory
+\isanewline
+%
+\endisadelimtheory
+\end{isabellebody}%
+%%% Local Variables:
+%%% mode: latex
+%%% TeX-master: "root"
+%%% End:
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/tphols-2011/generated/Myhill.tex Mon Jan 24 11:29:55 2011 +0000
@@ -0,0 +1,3856 @@
+%
+\begin{isabellebody}%
+\def\isabellecontext{Myhill}%
+%
+\isadelimtheory
+%
+\endisadelimtheory
+%
+\isatagtheory
+\isacommand{theory}\isamarkupfalse%
+\ Myhill\isanewline
+\ \ \isakeyword{imports}\ Main\ List{\isacharunderscore}Prefix\isanewline
+\isakeyword{begin}%
+\endisatagtheory
+{\isafoldtheory}%
+%
+\isadelimtheory
+%
+\endisadelimtheory
+%
+\isamarkupsection{Preliminary definitions%
+}
+\isamarkuptrue%
+%
+\begin{isamarkuptext}%
+Sequential composition of two languages \isa{L{\isadigit{1}}} and \isa{L{\isadigit{2}}}%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{definition}\isamarkupfalse%
+\ Seq\ {\isacharcolon}{\isacharcolon}\ {\isachardoublequoteopen}string\ set\ {\isasymRightarrow}\ string\ set\ {\isasymRightarrow}\ string\ set{\isachardoublequoteclose}\ {\isacharparenleft}{\isachardoublequoteopen}{\isacharunderscore}\ {\isacharsemicolon}{\isacharsemicolon}\ {\isacharunderscore}{\isachardoublequoteclose}\ {\isacharbrackleft}{\isadigit{1}}{\isadigit{0}}{\isadigit{0}}{\isacharcomma}{\isadigit{1}}{\isadigit{0}}{\isadigit{0}}{\isacharbrackright}\ {\isadigit{1}}{\isadigit{0}}{\isadigit{0}}{\isacharparenright}\isanewline
+\isakeyword{where}\ \isanewline
+\ \ {\isachardoublequoteopen}L{\isadigit{1}}\ {\isacharsemicolon}{\isacharsemicolon}\ L{\isadigit{2}}\ {\isacharequal}\ {\isacharbraceleft}s{\isadigit{1}}\ {\isacharat}\ s{\isadigit{2}}\ {\isacharbar}\ s{\isadigit{1}}\ s{\isadigit{2}}{\isachardot}\ s{\isadigit{1}}\ {\isasymin}\ L{\isadigit{1}}\ {\isasymand}\ s{\isadigit{2}}\ {\isasymin}\ L{\isadigit{2}}{\isacharbraceright}{\isachardoublequoteclose}%
+\begin{isamarkuptext}%
+Transitive closure of language \isa{L}.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{inductive{\isacharunderscore}set}\isamarkupfalse%
+\isanewline
+\ \ Star\ {\isacharcolon}{\isacharcolon}\ {\isachardoublequoteopen}string\ set\ {\isasymRightarrow}\ string\ set{\isachardoublequoteclose}\ {\isacharparenleft}{\isachardoublequoteopen}{\isacharunderscore}{\isasymstar}{\isachardoublequoteclose}\ {\isacharbrackleft}{\isadigit{1}}{\isadigit{0}}{\isadigit{1}}{\isacharbrackright}\ {\isadigit{1}}{\isadigit{0}}{\isadigit{2}}{\isacharparenright}\isanewline
+\ \ \isakeyword{for}\ L\ {\isacharcolon}{\isacharcolon}\ {\isachardoublequoteopen}string\ set{\isachardoublequoteclose}\isanewline
+\isakeyword{where}\isanewline
+\ \ start{\isacharbrackleft}intro{\isacharbrackright}{\isacharcolon}\ {\isachardoublequoteopen}{\isacharbrackleft}{\isacharbrackright}\ {\isasymin}\ L{\isasymstar}{\isachardoublequoteclose}\isanewline
+{\isacharbar}\ step{\isacharbrackleft}intro{\isacharbrackright}{\isacharcolon}\ \ {\isachardoublequoteopen}{\isasymlbrakk}s{\isadigit{1}}\ {\isasymin}\ L{\isacharsemicolon}\ s{\isadigit{2}}\ {\isasymin}\ L{\isasymstar}{\isasymrbrakk}\ {\isasymLongrightarrow}\ s{\isadigit{1}}{\isacharat}s{\isadigit{2}}\ {\isasymin}\ L{\isasymstar}{\isachardoublequoteclose}%
+\begin{isamarkuptext}%
+Some properties of operator \isa{{\isacharsemicolon}{\isacharsemicolon}}.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{lemma}\isamarkupfalse%
+\ seq{\isacharunderscore}union{\isacharunderscore}distrib{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}{\isacharparenleft}A\ {\isasymunion}\ B{\isacharparenright}\ {\isacharsemicolon}{\isacharsemicolon}\ C\ {\isacharequal}\ {\isacharparenleft}A\ {\isacharsemicolon}{\isacharsemicolon}\ C{\isacharparenright}\ {\isasymunion}\ {\isacharparenleft}B\ {\isacharsemicolon}{\isacharsemicolon}\ C{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}Seq{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ seq{\isacharunderscore}intro{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}{\isasymlbrakk}x\ {\isasymin}\ A{\isacharsemicolon}\ y\ {\isasymin}\ B{\isasymrbrakk}\ {\isasymLongrightarrow}\ x\ {\isacharat}\ y\ {\isasymin}\ A\ {\isacharsemicolon}{\isacharsemicolon}\ B\ {\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}Seq{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ seq{\isacharunderscore}assoc{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}{\isacharparenleft}A\ {\isacharsemicolon}{\isacharsemicolon}\ B{\isacharparenright}\ {\isacharsemicolon}{\isacharsemicolon}\ C\ {\isacharequal}\ A\ {\isacharsemicolon}{\isacharsemicolon}\ {\isacharparenleft}B\ {\isacharsemicolon}{\isacharsemicolon}\ C{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{apply}\isamarkupfalse%
+{\isacharparenleft}auto\ simp{\isacharcolon}Seq{\isacharunderscore}def{\isacharparenright}\isanewline
+\isacommand{apply}\isamarkupfalse%
+\ blast\isanewline
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}metis\ append{\isacharunderscore}assoc{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ star{\isacharunderscore}intro{\isadigit{1}}{\isacharbrackleft}rule{\isacharunderscore}format{\isacharbrackright}{\isacharcolon}\ {\isachardoublequoteopen}x\ {\isasymin}\ lang{\isasymstar}\ {\isasymLongrightarrow}\ {\isasymforall}\ y{\isachardot}\ y\ {\isasymin}\ lang{\isasymstar}\ {\isasymlongrightarrow}\ x\ {\isacharat}\ y\ {\isasymin}\ lang{\isasymstar}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}erule\ Star{\isachardot}induct{\isacharcomma}\ auto{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ star{\isacharunderscore}intro{\isadigit{2}}{\isacharcolon}\ {\isachardoublequoteopen}y\ {\isasymin}\ lang\ {\isasymLongrightarrow}\ y\ {\isasymin}\ lang{\isasymstar}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}drule\ step{\isacharbrackleft}of\ y\ lang\ {\isachardoublequoteopen}{\isacharbrackleft}{\isacharbrackright}{\isachardoublequoteclose}{\isacharbrackright}{\isacharcomma}\ auto\ simp{\isacharcolon}start{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ star{\isacharunderscore}intro{\isadigit{3}}{\isacharbrackleft}rule{\isacharunderscore}format{\isacharbrackright}{\isacharcolon}\ \isanewline
+\ \ {\isachardoublequoteopen}x\ {\isasymin}\ lang{\isasymstar}\ {\isasymLongrightarrow}\ {\isasymforall}y\ {\isachardot}\ y\ {\isasymin}\ lang\ {\isasymlongrightarrow}\ x\ {\isacharat}\ y\ {\isasymin}\ lang{\isasymstar}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}erule\ Star{\isachardot}induct{\isacharcomma}\ auto\ intro{\isacharcolon}star{\isacharunderscore}intro{\isadigit{2}}{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ star{\isacharunderscore}decom{\isacharcolon}\ \isanewline
+\ \ {\isachardoublequoteopen}{\isasymlbrakk}x\ {\isasymin}\ lang{\isasymstar}{\isacharsemicolon}\ x\ {\isasymnoteq}\ {\isacharbrackleft}{\isacharbrackright}{\isasymrbrakk}\ {\isasymLongrightarrow}{\isacharparenleft}{\isasymexists}\ a\ b{\isachardot}\ x\ {\isacharequal}\ a\ {\isacharat}\ b\ {\isasymand}\ a\ {\isasymnoteq}\ {\isacharbrackleft}{\isacharbrackright}\ {\isasymand}\ a\ {\isasymin}\ lang\ {\isasymand}\ b\ {\isasymin}\ lang{\isasymstar}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}induct\ x\ rule{\isacharcolon}\ Star{\isachardot}induct{\isacharcomma}\ simp{\isacharcomma}\ blast{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ star{\isacharunderscore}decom{\isacharprime}{\isacharcolon}\ \isanewline
+\ \ {\isachardoublequoteopen}{\isasymlbrakk}x\ {\isasymin}\ lang{\isasymstar}{\isacharsemicolon}\ x\ {\isasymnoteq}\ {\isacharbrackleft}{\isacharbrackright}{\isasymrbrakk}\ {\isasymLongrightarrow}\ {\isasymexists}a\ b{\isachardot}\ x\ {\isacharequal}\ a\ {\isacharat}\ b\ {\isasymand}\ a\ {\isasymin}\ lang{\isasymstar}\ {\isasymand}\ b\ {\isasymin}\ lang{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}induct\ x\ rule{\isacharcolon}Star{\isachardot}induct{\isacharcomma}\ simp{\isacharparenright}\isanewline
+\isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}case{\isacharunderscore}tac\ {\isachardoublequoteopen}s{\isadigit{2}}\ {\isacharequal}\ {\isacharbrackleft}{\isacharbrackright}{\isachardoublequoteclose}{\isacharparenright}\isanewline
+\isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}rule{\isacharunderscore}tac\ x\ {\isacharequal}\ {\isachardoublequoteopen}{\isacharbrackleft}{\isacharbrackright}{\isachardoublequoteclose}\ \isakeyword{in}\ exI{\isacharcomma}\ rule{\isacharunderscore}tac\ x\ {\isacharequal}\ s{\isadigit{1}}\ \isakeyword{in}\ exI{\isacharcomma}\ simp\ add{\isacharcolon}start{\isacharparenright}\isanewline
+\isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}simp{\isacharcomma}\ {\isacharparenleft}erule\ exE{\isacharbar}\ erule\ conjE{\isacharparenright}{\isacharplus}{\isacharparenright}\isanewline
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}rule{\isacharunderscore}tac\ x\ {\isacharequal}\ {\isachardoublequoteopen}s{\isadigit{1}}\ {\isacharat}\ a{\isachardoublequoteclose}\ \isakeyword{in}\ exI{\isacharcomma}\ rule{\isacharunderscore}tac\ x\ {\isacharequal}\ b\ \isakeyword{in}\ exI{\isacharcomma}\ simp\ add{\isacharcolon}step{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\begin{isamarkuptext}%
+Ardens lemma expressed at the level of language, rather than the level of regular expression.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{theorem}\isamarkupfalse%
+\ ardens{\isacharunderscore}revised{\isacharcolon}\isanewline
+\ \ \isakeyword{assumes}\ nemp{\isacharcolon}\ {\isachardoublequoteopen}{\isacharbrackleft}{\isacharbrackright}\ {\isasymnotin}\ A{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{shows}\ {\isachardoublequoteopen}{\isacharparenleft}X\ {\isacharequal}\ X\ {\isacharsemicolon}{\isacharsemicolon}\ A\ {\isasymunion}\ B{\isacharparenright}\ {\isasymlongleftrightarrow}\ {\isacharparenleft}X\ {\isacharequal}\ B\ {\isacharsemicolon}{\isacharsemicolon}\ A{\isasymstar}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{assume}\isamarkupfalse%
+\ eq{\isacharcolon}\ {\isachardoublequoteopen}X\ {\isacharequal}\ B\ {\isacharsemicolon}{\isacharsemicolon}\ A{\isasymstar}{\isachardoublequoteclose}\isanewline
+\ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}A{\isasymstar}\ {\isacharequal}\ \ {\isacharbraceleft}{\isacharbrackleft}{\isacharbrackright}{\isacharbraceright}\ {\isasymunion}\ A{\isasymstar}\ {\isacharsemicolon}{\isacharsemicolon}\ A{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}Seq{\isacharunderscore}def\ star{\isacharunderscore}intro{\isadigit{3}}\ star{\isacharunderscore}decom{\isacharprime}{\isacharparenright}\ \ \isanewline
+\ \ \isacommand{then}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}B\ {\isacharsemicolon}{\isacharsemicolon}\ A{\isasymstar}\ {\isacharequal}\ B\ {\isacharsemicolon}{\isacharsemicolon}\ {\isacharparenleft}{\isacharbraceleft}{\isacharbrackleft}{\isacharbrackright}{\isacharbraceright}\ {\isasymunion}\ A{\isasymstar}\ {\isacharsemicolon}{\isacharsemicolon}\ A{\isacharparenright}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \isacommand{unfolding}\isamarkupfalse%
+\ Seq{\isacharunderscore}def\ \isacommand{by}\isamarkupfalse%
+\ simp\isanewline
+\ \ \isacommand{also}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isasymdots}\ {\isacharequal}\ B\ {\isasymunion}\ B\ {\isacharsemicolon}{\isacharsemicolon}\ {\isacharparenleft}A{\isasymstar}\ {\isacharsemicolon}{\isacharsemicolon}\ A{\isacharparenright}{\isachardoublequoteclose}\ \ \isanewline
+\ \ \ \ \isacommand{unfolding}\isamarkupfalse%
+\ Seq{\isacharunderscore}def\ \isacommand{by}\isamarkupfalse%
+\ auto\isanewline
+\ \ \isacommand{also}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isasymdots}\ {\isacharequal}\ B\ {\isasymunion}\ {\isacharparenleft}B\ {\isacharsemicolon}{\isacharsemicolon}\ A{\isasymstar}{\isacharparenright}\ {\isacharsemicolon}{\isacharsemicolon}\ A{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}simp\ only{\isacharcolon}seq{\isacharunderscore}assoc{\isacharparenright}\isanewline
+\ \ \isacommand{finally}\isamarkupfalse%
+\ \isacommand{show}\isamarkupfalse%
+\ {\isachardoublequoteopen}X\ {\isacharequal}\ X\ {\isacharsemicolon}{\isacharsemicolon}\ A\ {\isasymunion}\ B{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \isacommand{using}\isamarkupfalse%
+\ eq\ \isacommand{by}\isamarkupfalse%
+\ blast\ \isanewline
+\isacommand{next}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{assume}\isamarkupfalse%
+\ eq{\isacharprime}{\isacharcolon}\ {\isachardoublequoteopen}X\ {\isacharequal}\ X\ {\isacharsemicolon}{\isacharsemicolon}\ A\ {\isasymunion}\ B{\isachardoublequoteclose}\isanewline
+\ \ \isacommand{hence}\isamarkupfalse%
+\ c{\isadigit{1}}{\isacharprime}{\isacharcolon}\ {\isachardoublequoteopen}{\isasymAnd}\ x{\isachardot}\ x\ {\isasymin}\ B\ {\isasymLongrightarrow}\ x\ {\isasymin}\ X{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \isakeyword{and}\ c{\isadigit{2}}{\isacharprime}{\isacharcolon}\ {\isachardoublequoteopen}{\isasymAnd}\ x\ y{\isachardot}\ {\isasymlbrakk}x\ {\isasymin}\ X{\isacharsemicolon}\ y\ {\isasymin}\ A{\isasymrbrakk}\ {\isasymLongrightarrow}\ x\ {\isacharat}\ y\ {\isasymin}\ X{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \isacommand{using}\isamarkupfalse%
+\ Seq{\isacharunderscore}def\ \isacommand{by}\isamarkupfalse%
+\ auto\isanewline
+\ \ \isacommand{show}\isamarkupfalse%
+\ {\isachardoublequoteopen}X\ {\isacharequal}\ B\ {\isacharsemicolon}{\isacharsemicolon}\ A{\isasymstar}{\isachardoublequoteclose}\ \isanewline
+\ \ \isacommand{proof}\isamarkupfalse%
+\isanewline
+\ \ \ \ \isacommand{show}\isamarkupfalse%
+\ {\isachardoublequoteopen}B\ {\isacharsemicolon}{\isacharsemicolon}\ A{\isasymstar}\ {\isasymsubseteq}\ X{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{proof}\isamarkupfalse%
+{\isacharminus}\isanewline
+\ \ \ \ \ \ \isacommand{{\isacharbraceleft}}\isamarkupfalse%
+\ \isacommand{fix}\isamarkupfalse%
+\ x\ y\isanewline
+\ \ \ \ \ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isasymlbrakk}y\ {\isasymin}\ A{\isasymstar}{\isacharsemicolon}\ x\ {\isasymin}\ X{\isasymrbrakk}\ {\isasymLongrightarrow}\ x\ {\isacharat}\ y\ {\isasymin}\ X\ {\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \ \ \ \ \isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}induct\ arbitrary{\isacharcolon}x\ rule{\isacharcolon}Star{\isachardot}induct{\isacharcomma}\ simp{\isacharparenright}\isanewline
+\ \ \ \ \ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp\ only{\isacharcolon}append{\isacharunderscore}assoc{\isacharbrackleft}THEN\ sym{\isacharbrackright}\ dest{\isacharcolon}c{\isadigit{2}}{\isacharprime}{\isacharparenright}\isanewline
+\ \ \ \ \ \ \isacommand{{\isacharbraceright}}\isamarkupfalse%
+\ \isacommand{thus}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{using}\isamarkupfalse%
+\ c{\isadigit{1}}{\isacharprime}\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}Seq{\isacharunderscore}def{\isacharparenright}\ \isanewline
+\ \ \ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{next}\isamarkupfalse%
+\isanewline
+\ \ \ \ \isacommand{show}\isamarkupfalse%
+\ {\isachardoublequoteopen}X\ {\isasymsubseteq}\ B\ {\isacharsemicolon}{\isacharsemicolon}\ A{\isasymstar}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{proof}\isamarkupfalse%
+{\isacharminus}\isanewline
+\ \ \ \ \ \ \isacommand{{\isacharbraceleft}}\isamarkupfalse%
+\ \isacommand{fix}\isamarkupfalse%
+\ x\ \isanewline
+\ \ \ \ \ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}x\ {\isasymin}\ X\ {\isasymLongrightarrow}\ x\ {\isasymin}\ B\ {\isacharsemicolon}{\isacharsemicolon}\ A{\isasymstar}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \ \ \isacommand{proof}\isamarkupfalse%
+\ {\isacharparenleft}induct\ x\ taking{\isacharcolon}length\ rule{\isacharcolon}measure{\isacharunderscore}induct{\isacharparenright}\isanewline
+\ \ \ \ \ \ \ \ \ \ \isacommand{fix}\isamarkupfalse%
+\ z\isanewline
+\ \ \ \ \ \ \ \ \ \ \isacommand{assume}\isamarkupfalse%
+\ hyps{\isacharcolon}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ {\isachardoublequoteopen}{\isasymforall}y{\isachardot}\ length\ y\ {\isacharless}\ length\ z\ {\isasymlongrightarrow}\ y\ {\isasymin}\ X\ {\isasymlongrightarrow}\ y\ {\isasymin}\ B\ {\isacharsemicolon}{\isacharsemicolon}\ A{\isasymstar}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \isakeyword{and}\ z{\isacharunderscore}in{\isacharcolon}\ {\isachardoublequoteopen}z\ {\isasymin}\ X{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \ \ \ \ \isacommand{show}\isamarkupfalse%
+\ {\isachardoublequoteopen}z\ {\isasymin}\ B\ {\isacharsemicolon}{\isacharsemicolon}\ A{\isasymstar}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \ \ \ \ \isacommand{proof}\isamarkupfalse%
+\ {\isacharparenleft}cases\ {\isachardoublequoteopen}z\ {\isasymin}\ B{\isachardoublequoteclose}{\isacharparenright}\isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \isacommand{case}\isamarkupfalse%
+\ True\ \isacommand{thus}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}Seq{\isacharunderscore}def\ start{\isacharparenright}\isanewline
+\ \ \ \ \ \ \ \ \ \ \isacommand{next}\isamarkupfalse%
+\isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \isacommand{case}\isamarkupfalse%
+\ False\ \isacommand{hence}\isamarkupfalse%
+\ {\isachardoublequoteopen}z\ {\isasymin}\ X\ {\isacharsemicolon}{\isacharsemicolon}\ A{\isachardoublequoteclose}\ \isacommand{using}\isamarkupfalse%
+\ eq{\isacharprime}\ z{\isacharunderscore}in\ \isacommand{by}\isamarkupfalse%
+\ auto\isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \isacommand{then}\isamarkupfalse%
+\ \isacommand{obtain}\isamarkupfalse%
+\ za\ zb\ \isakeyword{where}\ za{\isacharunderscore}in{\isacharcolon}\ {\isachardoublequoteopen}za\ {\isasymin}\ X{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \isakeyword{and}\ zab{\isacharcolon}\ {\isachardoublequoteopen}z\ {\isacharequal}\ za\ {\isacharat}\ zb\ {\isasymand}\ zb\ {\isasymin}\ A{\isachardoublequoteclose}\ \isakeyword{and}\ zbne{\isacharcolon}\ {\isachardoublequoteopen}zb\ {\isasymnoteq}\ {\isacharbrackleft}{\isacharbrackright}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \isacommand{using}\isamarkupfalse%
+\ nemp\ \isacommand{unfolding}\isamarkupfalse%
+\ Seq{\isacharunderscore}def\ \isacommand{by}\isamarkupfalse%
+\ blast\isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \isacommand{from}\isamarkupfalse%
+\ zbne\ zab\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}length\ za\ {\isacharless}\ length\ z{\isachardoublequoteclose}\ \isacommand{by}\isamarkupfalse%
+\ auto\isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \isacommand{with}\isamarkupfalse%
+\ za{\isacharunderscore}in\ hyps\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}za\ {\isasymin}\ B\ {\isacharsemicolon}{\isacharsemicolon}\ A{\isasymstar}{\isachardoublequoteclose}\ \isacommand{by}\isamarkupfalse%
+\ blast\isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \isacommand{hence}\isamarkupfalse%
+\ {\isachardoublequoteopen}za\ {\isacharat}\ zb\ {\isasymin}\ B\ {\isacharsemicolon}{\isacharsemicolon}\ A{\isasymstar}{\isachardoublequoteclose}\ \isacommand{using}\isamarkupfalse%
+\ zab\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}clarsimp\ simp{\isacharcolon}Seq{\isacharunderscore}def{\isacharcomma}\ blast\ dest{\isacharcolon}star{\isacharunderscore}intro{\isadigit{3}}{\isacharparenright}\isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \isacommand{thus}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{using}\isamarkupfalse%
+\ zab\ \isacommand{by}\isamarkupfalse%
+\ simp\ \ \ \ \ \ \ \isanewline
+\ \ \ \ \ \ \ \ \ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\ \ \ \ \ \ \ \ \isacommand{qed}\isamarkupfalse%
+\ \isanewline
+\ \ \ \ \ \ \isacommand{{\isacharbraceright}}\isamarkupfalse%
+\ \isacommand{thus}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ blast\isanewline
+\ \ \ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\begin{isamarkuptext}%
+The syntax of regular expressions is defined by the datatype \isa{rexp}.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{datatype}\isamarkupfalse%
+\ rexp\ {\isacharequal}\isanewline
+\ \ NULL\isanewline
+{\isacharbar}\ EMPTY\isanewline
+{\isacharbar}\ CHAR\ char\isanewline
+{\isacharbar}\ SEQ\ rexp\ rexp\isanewline
+{\isacharbar}\ ALT\ rexp\ rexp\isanewline
+{\isacharbar}\ STAR\ rexp%
+\begin{isamarkuptext}%
+The following \isa{L} is an overloaded operator, where \isa{L{\isacharparenleft}x{\isacharparenright}} evaluates to
+ the language represented by the syntactic object \isa{x}.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{consts}\isamarkupfalse%
+\ L{\isacharcolon}{\isacharcolon}\ {\isachardoublequoteopen}{\isacharprime}a\ {\isasymRightarrow}\ string\ set{\isachardoublequoteclose}%
+\begin{isamarkuptext}%
+The \isa{L{\isacharparenleft}rexp{\isacharparenright}} for regular expression \isa{rexp} is defined by the
+ following overloading function \isa{L{\isacharunderscore}rexp}.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{overloading}\isamarkupfalse%
+\ L{\isacharunderscore}rexp\ {\isasymequiv}\ {\isachardoublequoteopen}L{\isacharcolon}{\isacharcolon}\ \ rexp\ {\isasymRightarrow}\ string\ set{\isachardoublequoteclose}\isanewline
+\isakeyword{begin}\isanewline
+\isacommand{fun}\isamarkupfalse%
+\isanewline
+\ \ L{\isacharunderscore}rexp\ {\isacharcolon}{\isacharcolon}\ {\isachardoublequoteopen}rexp\ {\isasymRightarrow}\ string\ set{\isachardoublequoteclose}\isanewline
+\isakeyword{where}\isanewline
+\ \ \ \ {\isachardoublequoteopen}L{\isacharunderscore}rexp\ {\isacharparenleft}NULL{\isacharparenright}\ {\isacharequal}\ {\isacharbraceleft}{\isacharbraceright}{\isachardoublequoteclose}\isanewline
+\ \ {\isacharbar}\ {\isachardoublequoteopen}L{\isacharunderscore}rexp\ {\isacharparenleft}EMPTY{\isacharparenright}\ {\isacharequal}\ {\isacharbraceleft}{\isacharbrackleft}{\isacharbrackright}{\isacharbraceright}{\isachardoublequoteclose}\isanewline
+\ \ {\isacharbar}\ {\isachardoublequoteopen}L{\isacharunderscore}rexp\ {\isacharparenleft}CHAR\ c{\isacharparenright}\ {\isacharequal}\ {\isacharbraceleft}{\isacharbrackleft}c{\isacharbrackright}{\isacharbraceright}{\isachardoublequoteclose}\isanewline
+\ \ {\isacharbar}\ {\isachardoublequoteopen}L{\isacharunderscore}rexp\ {\isacharparenleft}SEQ\ r{\isadigit{1}}\ r{\isadigit{2}}{\isacharparenright}\ {\isacharequal}\ {\isacharparenleft}L{\isacharunderscore}rexp\ r{\isadigit{1}}{\isacharparenright}\ {\isacharsemicolon}{\isacharsemicolon}\ {\isacharparenleft}L{\isacharunderscore}rexp\ r{\isadigit{2}}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ {\isacharbar}\ {\isachardoublequoteopen}L{\isacharunderscore}rexp\ {\isacharparenleft}ALT\ r{\isadigit{1}}\ r{\isadigit{2}}{\isacharparenright}\ {\isacharequal}\ {\isacharparenleft}L{\isacharunderscore}rexp\ r{\isadigit{1}}{\isacharparenright}\ {\isasymunion}\ {\isacharparenleft}L{\isacharunderscore}rexp\ r{\isadigit{2}}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ {\isacharbar}\ {\isachardoublequoteopen}L{\isacharunderscore}rexp\ {\isacharparenleft}STAR\ r{\isacharparenright}\ {\isacharequal}\ {\isacharparenleft}L{\isacharunderscore}rexp\ r{\isacharparenright}{\isasymstar}{\isachardoublequoteclose}\isanewline
+\isacommand{end}\isamarkupfalse%
+%
+\begin{isamarkuptext}%
+To obtain equational system out of finite set of equivalent classes, a fold operation
+ on finite set \isa{folds} is defined. The use of \isa{SOME} makes \isa{fold}
+ more robust than the \isa{fold} in Isabelle library. The expression \isa{folds\ f}
+ makes sense when \isa{f} is not \isa{associative} and \isa{commutitive},
+ while \isa{fold\ f} does not.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{definition}\isamarkupfalse%
+\ \isanewline
+\ \ folds\ {\isacharcolon}{\isacharcolon}\ {\isachardoublequoteopen}{\isacharparenleft}{\isacharprime}a\ {\isasymRightarrow}\ {\isacharprime}b\ {\isasymRightarrow}\ {\isacharprime}b{\isacharparenright}\ {\isasymRightarrow}\ {\isacharprime}b\ {\isasymRightarrow}\ {\isacharprime}a\ set\ {\isasymRightarrow}\ {\isacharprime}b{\isachardoublequoteclose}\isanewline
+\isakeyword{where}\isanewline
+\ \ {\isachardoublequoteopen}folds\ f\ z\ S\ {\isasymequiv}\ SOME\ x{\isachardot}\ fold{\isacharunderscore}graph\ f\ z\ S\ x{\isachardoublequoteclose}%
+\begin{isamarkuptext}%
+The following lemma assures that the arbitrary choice made by the \isa{SOME} in \isa{folds}
+ does not affect the \isa{L}-value of the resultant regular expression.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{lemma}\isamarkupfalse%
+\ folds{\isacharunderscore}alt{\isacharunderscore}simp\ {\isacharbrackleft}simp{\isacharbrackright}{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}finite\ rs\ {\isasymLongrightarrow}\ L\ {\isacharparenleft}folds\ ALT\ NULL\ rs{\isacharparenright}\ {\isacharequal}\ {\isasymUnion}\ {\isacharparenleft}L\ {\isacharbackquote}\ rs{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}rule\ set{\isacharunderscore}ext{\isacharcomma}\ simp\ add{\isacharcolon}folds{\isacharunderscore}def{\isacharparenright}\isanewline
+\isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}rule\ someI{\isadigit{2}}{\isacharunderscore}ex{\isacharcomma}\ erule\ finite{\isacharunderscore}imp{\isacharunderscore}fold{\isacharunderscore}graph{\isacharparenright}\isanewline
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}erule\ fold{\isacharunderscore}graph{\isachardot}induct{\isacharcomma}\ auto{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ {\isacharbrackleft}simp{\isacharbrackright}{\isacharcolon}\isanewline
+\ \ \isakeyword{shows}\ {\isachardoublequoteopen}{\isacharparenleft}x{\isacharcomma}\ y{\isacharparenright}\ {\isasymin}\ {\isacharbraceleft}{\isacharparenleft}x{\isacharcomma}\ y{\isacharparenright}{\isachardot}\ P\ x\ y{\isacharbraceright}\ {\isasymlongleftrightarrow}\ P\ x\ y{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ simp%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\begin{isamarkuptext}%
+\isa{{\isasymapprox}L} is an equivalent class defined by language \isa{Lang}.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{definition}\isamarkupfalse%
+\isanewline
+\ \ str{\isacharunderscore}eq{\isacharunderscore}rel\ {\isacharparenleft}{\isachardoublequoteopen}{\isasymapprox}{\isacharunderscore}{\isachardoublequoteclose}{\isacharparenright}\isanewline
+\isakeyword{where}\isanewline
+\ \ {\isachardoublequoteopen}{\isasymapprox}Lang\ {\isasymequiv}\ {\isacharbraceleft}{\isacharparenleft}x{\isacharcomma}\ y{\isacharparenright}{\isachardot}\ \ {\isacharparenleft}{\isasymforall}z{\isachardot}\ x\ {\isacharat}\ z\ {\isasymin}\ Lang\ {\isasymlongleftrightarrow}\ y\ {\isacharat}\ z\ {\isasymin}\ Lang{\isacharparenright}{\isacharbraceright}{\isachardoublequoteclose}%
+\begin{isamarkuptext}%
+Among equivlant clases of \isa{{\isasymapprox}Lang}, the set \isa{finals{\isacharparenleft}Lang{\isacharparenright}} singles out
+ those which contains strings from \isa{Lang}.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{definition}\isamarkupfalse%
+\ \isanewline
+\ \ \ {\isachardoublequoteopen}finals\ Lang\ {\isasymequiv}\ {\isacharbraceleft}{\isasymapprox}Lang\ {\isacharbackquote}{\isacharbackquote}\ {\isacharbraceleft}x{\isacharbraceright}\ {\isacharbar}\ x\ {\isachardot}\ x\ {\isasymin}\ Lang{\isacharbraceright}{\isachardoublequoteclose}%
+\begin{isamarkuptext}%
+The following lemma show the relationshipt between \isa{finals{\isacharparenleft}Lang{\isacharparenright}} and \isa{Lang}.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{lemma}\isamarkupfalse%
+\ lang{\isacharunderscore}is{\isacharunderscore}union{\isacharunderscore}of{\isacharunderscore}finals{\isacharcolon}\ \isanewline
+\ \ {\isachardoublequoteopen}Lang\ {\isacharequal}\ {\isasymUnion}\ finals{\isacharparenleft}Lang{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+\ \isanewline
+\ \ \isacommand{show}\isamarkupfalse%
+\ {\isachardoublequoteopen}Lang\ {\isasymsubseteq}\ {\isasymUnion}\ {\isacharparenleft}finals\ Lang{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \isacommand{proof}\isamarkupfalse%
+\isanewline
+\ \ \ \ \isacommand{fix}\isamarkupfalse%
+\ x\isanewline
+\ \ \ \ \isacommand{assume}\isamarkupfalse%
+\ {\isachardoublequoteopen}x\ {\isasymin}\ Lang{\isachardoublequoteclose}\ \ \ \isanewline
+\ \ \ \ \isacommand{thus}\isamarkupfalse%
+\ {\isachardoublequoteopen}x\ {\isasymin}\ {\isasymUnion}\ {\isacharparenleft}finals\ Lang{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}simp\ add{\isacharcolon}finals{\isacharunderscore}def{\isacharcomma}\ rule{\isacharunderscore}tac\ x\ {\isacharequal}\ {\isachardoublequoteopen}{\isacharparenleft}{\isasymapprox}Lang{\isacharparenright}\ {\isacharbackquote}{\isacharbackquote}\ {\isacharbraceleft}x{\isacharbraceright}{\isachardoublequoteclose}\ \isakeyword{in}\ exI{\isacharparenright}\isanewline
+\ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}Image{\isacharunderscore}def\ str{\isacharunderscore}eq{\isacharunderscore}rel{\isacharunderscore}def{\isacharparenright}\ \ \ \ \isanewline
+\ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\isacommand{next}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{show}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isasymUnion}\ {\isacharparenleft}finals\ Lang{\isacharparenright}\ {\isasymsubseteq}\ Lang{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}clarsimp\ simp{\isacharcolon}finals{\isacharunderscore}def\ str{\isacharunderscore}eq{\isacharunderscore}rel{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}drule{\isacharunderscore}tac\ x\ {\isacharequal}\ {\isachardoublequoteopen}{\isacharbrackleft}{\isacharbrackright}{\isachardoublequoteclose}\ \isakeyword{in}\ spec{\isacharcomma}\ auto{\isacharparenright}\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isamarkupsection{Direction \isa{finite\ partition\ {\isasymRightarrow}\ regular\ language}%
+}
+\isamarkuptrue%
+%
+\begin{isamarkuptext}%
+The relationship between equivalent classes can be described by an
+ equational system.
+ For example, in equational system \eqref{example_eqns}, $X_0, X_1$ are equivalent
+ classes. The first equation says every string in $X_0$ is obtained either by
+ appending one $b$ to a string in $X_0$ or by appending one $a$ to a string in
+ $X_1$ or just be an empty string (represented by the regular expression $\lambda$). Similary,
+ the second equation tells how the strings inside $X_1$ are composed.
+ \begin{equation}\label{example_eqns}
+ \begin{aligned}
+ X_0 & = X_0 b + X_1 a + \lambda \\
+ X_1 & = X_0 a + X_1 b
+ \end{aligned}
+ \end{equation}
+ The summands on the right hand side is represented by the following data type
+ \isa{rhs{\isacharunderscore}item}, mnemonic for 'right hand side item'.
+ Generally, there are two kinds of right hand side items, one kind corresponds to
+ pure regular expressions, like the $\lambda$ in \eqref{example_eqns}, the other kind corresponds to
+ transitions from one one equivalent class to another, like the $X_0 b, X_1 a$ etc.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{datatype}\isamarkupfalse%
+\ rhs{\isacharunderscore}item\ {\isacharequal}\ \isanewline
+\ \ \ Lam\ {\isachardoublequoteopen}rexp{\isachardoublequoteclose}\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \isanewline
+\ {\isacharbar}\ Trn\ {\isachardoublequoteopen}{\isacharparenleft}string\ set{\isacharparenright}{\isachardoublequoteclose}\ {\isachardoublequoteopen}rexp{\isachardoublequoteclose}%
+\begin{isamarkuptext}%
+In this formalization, pure regular expressions like $\lambda$ is
+ repsented by \isa{Lam{\isacharparenleft}EMPTY{\isacharparenright}}, while transitions like $X_0 a$ is represented by $Trn~X_0~(CHAR~a)$.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+%
+\begin{isamarkuptext}%
+The functions \isa{the{\isacharunderscore}r} and \isa{the{\isacharunderscore}Trn} are used to extract
+ subcomponents from right hand side items.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{fun}\isamarkupfalse%
+\ the{\isacharunderscore}r\ {\isacharcolon}{\isacharcolon}\ {\isachardoublequoteopen}rhs{\isacharunderscore}item\ {\isasymRightarrow}\ rexp{\isachardoublequoteclose}\isanewline
+\isakeyword{where}\ {\isachardoublequoteopen}the{\isacharunderscore}r\ {\isacharparenleft}Lam\ r{\isacharparenright}\ {\isacharequal}\ r{\isachardoublequoteclose}\isanewline
+\isanewline
+\isacommand{fun}\isamarkupfalse%
+\ the{\isacharunderscore}Trn{\isacharcolon}{\isacharcolon}\ {\isachardoublequoteopen}rhs{\isacharunderscore}item\ {\isasymRightarrow}\ {\isacharparenleft}string\ set\ {\isasymtimes}\ rexp{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\isakeyword{where}\ {\isachardoublequoteopen}the{\isacharunderscore}Trn\ {\isacharparenleft}Trn\ Y\ r{\isacharparenright}\ {\isacharequal}\ {\isacharparenleft}Y{\isacharcomma}\ r{\isacharparenright}{\isachardoublequoteclose}%
+\begin{isamarkuptext}%
+Every right hand side item \isa{itm} defines a string set given
+ \isa{L{\isacharparenleft}itm{\isacharparenright}}, defined as:%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{overloading}\isamarkupfalse%
+\ L{\isacharunderscore}rhs{\isacharunderscore}e\ {\isasymequiv}\ {\isachardoublequoteopen}L{\isacharcolon}{\isacharcolon}\ rhs{\isacharunderscore}item\ {\isasymRightarrow}\ string\ set{\isachardoublequoteclose}\isanewline
+\isakeyword{begin}\isanewline
+\ \ \isacommand{fun}\isamarkupfalse%
+\ L{\isacharunderscore}rhs{\isacharunderscore}e{\isacharcolon}{\isacharcolon}\ {\isachardoublequoteopen}rhs{\isacharunderscore}item\ {\isasymRightarrow}\ string\ set{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{where}\isanewline
+\ \ \ \ \ {\isachardoublequoteopen}L{\isacharunderscore}rhs{\isacharunderscore}e\ {\isacharparenleft}Lam\ r{\isacharparenright}\ {\isacharequal}\ L\ r{\isachardoublequoteclose}\ {\isacharbar}\isanewline
+\ \ \ \ \ {\isachardoublequoteopen}L{\isacharunderscore}rhs{\isacharunderscore}e\ {\isacharparenleft}Trn\ X\ r{\isacharparenright}\ {\isacharequal}\ X\ {\isacharsemicolon}{\isacharsemicolon}\ L\ r{\isachardoublequoteclose}\isanewline
+\isacommand{end}\isamarkupfalse%
+%
+\begin{isamarkuptext}%
+The right hand side of every equation is represented by a set of
+ items. The string set defined by such a set \isa{itms} is given
+ by \isa{L{\isacharparenleft}itms{\isacharparenright}}, defined as:%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{overloading}\isamarkupfalse%
+\ L{\isacharunderscore}rhs\ {\isasymequiv}\ {\isachardoublequoteopen}L{\isacharcolon}{\isacharcolon}\ rhs{\isacharunderscore}item\ set\ {\isasymRightarrow}\ string\ set{\isachardoublequoteclose}\isanewline
+\isakeyword{begin}\isanewline
+\ \ \ \isacommand{fun}\isamarkupfalse%
+\ L{\isacharunderscore}rhs{\isacharcolon}{\isacharcolon}\ {\isachardoublequoteopen}rhs{\isacharunderscore}item\ set\ {\isasymRightarrow}\ string\ set{\isachardoublequoteclose}\isanewline
+\ \ \ \isakeyword{where}\ {\isachardoublequoteopen}L{\isacharunderscore}rhs\ rhs\ {\isacharequal}\ {\isasymUnion}\ {\isacharparenleft}L\ {\isacharbackquote}\ rhs{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\isacommand{end}\isamarkupfalse%
+%
+\begin{isamarkuptext}%
+Given a set of equivalent classses \isa{CS} and one equivalent class \isa{X} among
+ \isa{CS}, the term \isa{init{\isacharunderscore}rhs\ CS\ X} is used to extract the right hand side of
+ the equation describing the formation of \isa{X}. The definition of \isa{init{\isacharunderscore}rhs}
+ is:%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{definition}\isamarkupfalse%
+\isanewline
+\ \ {\isachardoublequoteopen}init{\isacharunderscore}rhs\ CS\ X\ {\isasymequiv}\ \ \isanewline
+\ \ \ \ \ \ if\ {\isacharparenleft}{\isacharbrackleft}{\isacharbrackright}\ {\isasymin}\ X{\isacharparenright}\ then\ \isanewline
+\ \ \ \ \ \ \ \ \ \ {\isacharbraceleft}Lam{\isacharparenleft}EMPTY{\isacharparenright}{\isacharbraceright}\ {\isasymunion}\ {\isacharbraceleft}Trn\ Y\ {\isacharparenleft}CHAR\ c{\isacharparenright}\ {\isacharbar}\ Y\ c{\isachardot}\ Y\ {\isasymin}\ CS\ {\isasymand}\ Y\ {\isacharsemicolon}{\isacharsemicolon}\ {\isacharbraceleft}{\isacharbrackleft}c{\isacharbrackright}{\isacharbraceright}\ {\isasymsubseteq}\ X{\isacharbraceright}\isanewline
+\ \ \ \ \ \ else\ \isanewline
+\ \ \ \ \ \ \ \ \ \ {\isacharbraceleft}Trn\ Y\ {\isacharparenleft}CHAR\ c{\isacharparenright}{\isacharbar}\ Y\ c{\isachardot}\ Y\ {\isasymin}\ CS\ {\isasymand}\ Y\ {\isacharsemicolon}{\isacharsemicolon}\ {\isacharbraceleft}{\isacharbrackleft}c{\isacharbrackright}{\isacharbraceright}\ {\isasymsubseteq}\ X{\isacharbraceright}{\isachardoublequoteclose}%
+\begin{isamarkuptext}%
+In the definition of \isa{init{\isacharunderscore}rhs}, the term
+ \isa{{\isacharbraceleft}Trn\ Y\ {\isacharparenleft}CHAR\ c{\isacharparenright}{\isacharbar}\ Y\ c{\isachardot}\ Y\ {\isasymin}\ CS\ {\isasymand}\ Y\ {\isacharsemicolon}{\isacharsemicolon}\ {\isacharbraceleft}{\isacharbrackleft}c{\isacharbrackright}{\isacharbraceright}\ {\isasymsubseteq}\ X{\isacharbraceright}} appearing on both branches
+ describes the formation of strings in \isa{X} out of transitions, while
+ the term \isa{{\isacharbraceleft}Lam{\isacharparenleft}EMPTY{\isacharparenright}{\isacharbraceright}} describes the empty string which is intrinsically contained in
+ \isa{X} rather than by transition. This \isa{{\isacharbraceleft}Lam{\isacharparenleft}EMPTY{\isacharparenright}{\isacharbraceright}} corresponds to
+ the $\lambda$ in \eqref{example_eqns}.
+
+ With the help of \isa{init{\isacharunderscore}rhs}, the equitional system descrbing the formation of every
+ equivalent class inside \isa{CS} is given by the following \isa{eqs{\isacharparenleft}CS{\isacharparenright}}.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{definition}\isamarkupfalse%
+\ {\isachardoublequoteopen}eqs\ CS\ {\isasymequiv}\ {\isacharbraceleft}{\isacharparenleft}X{\isacharcomma}\ init{\isacharunderscore}rhs\ CS\ X{\isacharparenright}\ {\isacharbar}\ X{\isachardot}\ \ X\ {\isasymin}\ CS{\isacharbraceright}{\isachardoublequoteclose}%
+\begin{isamarkuptext}%
+The following \isa{items{\isacharunderscore}of\ rhs\ X} returns all \isa{X}-items in \isa{rhs}.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{definition}\isamarkupfalse%
+\isanewline
+\ \ {\isachardoublequoteopen}items{\isacharunderscore}of\ rhs\ X\ {\isasymequiv}\ {\isacharbraceleft}Trn\ X\ r\ {\isacharbar}\ r{\isachardot}\ {\isacharparenleft}Trn\ X\ r{\isacharparenright}\ {\isasymin}\ rhs{\isacharbraceright}{\isachardoublequoteclose}%
+\begin{isamarkuptext}%
+The following \isa{rexp{\isacharunderscore}of\ rhs\ X} combines all regular expressions in \isa{X}-items
+ using \isa{ALT} to form a single regular expression.
+ It will be used later to implement \isa{arden{\isacharunderscore}variate} and \isa{rhs{\isacharunderscore}subst}.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{definition}\isamarkupfalse%
+\ \isanewline
+\ \ {\isachardoublequoteopen}rexp{\isacharunderscore}of\ rhs\ X\ {\isasymequiv}\ folds\ ALT\ NULL\ {\isacharparenleft}{\isacharparenleft}snd\ o\ the{\isacharunderscore}Trn{\isacharparenright}\ {\isacharbackquote}\ items{\isacharunderscore}of\ rhs\ X{\isacharparenright}{\isachardoublequoteclose}%
+\begin{isamarkuptext}%
+The following \isa{lam{\isacharunderscore}of\ rhs} returns all pure regular expression items in \isa{rhs}.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{definition}\isamarkupfalse%
+\isanewline
+\ \ {\isachardoublequoteopen}lam{\isacharunderscore}of\ rhs\ {\isasymequiv}\ {\isacharbraceleft}Lam\ r\ {\isacharbar}\ r{\isachardot}\ Lam\ r\ {\isasymin}\ rhs{\isacharbraceright}{\isachardoublequoteclose}%
+\begin{isamarkuptext}%
+The following \isa{rexp{\isacharunderscore}of{\isacharunderscore}lam\ rhs} combines pure regular expression items in \isa{rhs}
+ using \isa{ALT} to form a single regular expression.
+ When all variables inside \isa{rhs} are eliminated, \isa{rexp{\isacharunderscore}of{\isacharunderscore}lam\ rhs}
+ is used to compute compute the regular expression corresponds to \isa{rhs}.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{definition}\isamarkupfalse%
+\isanewline
+\ \ {\isachardoublequoteopen}rexp{\isacharunderscore}of{\isacharunderscore}lam\ rhs\ {\isasymequiv}\ folds\ ALT\ NULL\ {\isacharparenleft}the{\isacharunderscore}r\ {\isacharbackquote}\ lam{\isacharunderscore}of\ rhs{\isacharparenright}{\isachardoublequoteclose}%
+\begin{isamarkuptext}%
+The following \isa{attach{\isacharunderscore}rexp\ rexp{\isacharprime}\ itm} attach
+ the regular expression \isa{rexp{\isacharprime}} to
+ the right of right hand side item \isa{itm}.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{fun}\isamarkupfalse%
+\ attach{\isacharunderscore}rexp\ {\isacharcolon}{\isacharcolon}\ {\isachardoublequoteopen}rexp\ {\isasymRightarrow}\ rhs{\isacharunderscore}item\ {\isasymRightarrow}\ rhs{\isacharunderscore}item{\isachardoublequoteclose}\isanewline
+\isakeyword{where}\isanewline
+\ \ {\isachardoublequoteopen}attach{\isacharunderscore}rexp\ rexp{\isacharprime}\ {\isacharparenleft}Lam\ rexp{\isacharparenright}\ \ \ {\isacharequal}\ Lam\ {\isacharparenleft}SEQ\ rexp\ rexp{\isacharprime}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+{\isacharbar}\ {\isachardoublequoteopen}attach{\isacharunderscore}rexp\ rexp{\isacharprime}\ {\isacharparenleft}Trn\ X\ rexp{\isacharparenright}\ {\isacharequal}\ Trn\ X\ {\isacharparenleft}SEQ\ rexp\ rexp{\isacharprime}{\isacharparenright}{\isachardoublequoteclose}%
+\begin{isamarkuptext}%
+The following \isa{append{\isacharunderscore}rhs{\isacharunderscore}rexp\ rhs\ rexp} attaches
+ \isa{rexp} to every item in \isa{rhs}.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{definition}\isamarkupfalse%
+\isanewline
+\ \ {\isachardoublequoteopen}append{\isacharunderscore}rhs{\isacharunderscore}rexp\ rhs\ rexp\ {\isasymequiv}\ {\isacharparenleft}attach{\isacharunderscore}rexp\ rexp{\isacharparenright}\ {\isacharbackquote}\ rhs{\isachardoublequoteclose}%
+\begin{isamarkuptext}%
+With the help of the two functions immediately above, Ardens'
+ transformation on right hand side \isa{rhs} is implemented
+ by the following function \isa{arden{\isacharunderscore}variate\ X\ rhs}.
+ After this transformation, the recursive occurent of \isa{X}
+ in \isa{rhs} will be eliminated, while the
+ string set defined by \isa{rhs} is kept unchanged.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{definition}\isamarkupfalse%
+\ \isanewline
+\ \ {\isachardoublequoteopen}arden{\isacharunderscore}variate\ X\ rhs\ {\isasymequiv}\ \isanewline
+\ \ \ \ \ \ \ \ append{\isacharunderscore}rhs{\isacharunderscore}rexp\ {\isacharparenleft}rhs\ {\isacharminus}\ items{\isacharunderscore}of\ rhs\ X{\isacharparenright}\ {\isacharparenleft}STAR\ {\isacharparenleft}rexp{\isacharunderscore}of\ rhs\ X{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}%
+\begin{isamarkuptext}%
+Suppose the equation defining \isa{X} is $X = xrhs$,
+ the purpose of \isa{rhs{\isacharunderscore}subst} is to substitute all occurences of \isa{X} in
+ \isa{rhs} by \isa{xrhs}.
+ A litte thought may reveal that the final result
+ should be: first append $(a_1 | a_2 | \ldots | a_n)$ to every item of \isa{xrhs} and then
+ union the result with all non-\isa{X}-items of \isa{rhs}.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{definition}\isamarkupfalse%
+\ \isanewline
+\ \ {\isachardoublequoteopen}rhs{\isacharunderscore}subst\ rhs\ X\ xrhs\ {\isasymequiv}\ \isanewline
+\ \ \ \ \ \ \ \ {\isacharparenleft}rhs\ {\isacharminus}\ {\isacharparenleft}items{\isacharunderscore}of\ rhs\ X{\isacharparenright}{\isacharparenright}\ {\isasymunion}\ {\isacharparenleft}append{\isacharunderscore}rhs{\isacharunderscore}rexp\ xrhs\ {\isacharparenleft}rexp{\isacharunderscore}of\ rhs\ X{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}%
+\begin{isamarkuptext}%
+Suppose the equation defining \isa{X} is $X = xrhs$, the follwing
+ \isa{eqs{\isacharunderscore}subst\ ES\ X\ xrhs} substitute \isa{xrhs} into every equation
+ of the equational system \isa{ES}.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{definition}\isamarkupfalse%
+\isanewline
+\ \ {\isachardoublequoteopen}eqs{\isacharunderscore}subst\ ES\ X\ xrhs\ {\isasymequiv}\ {\isacharbraceleft}{\isacharparenleft}Y{\isacharcomma}\ rhs{\isacharunderscore}subst\ yrhs\ X\ xrhs{\isacharparenright}\ {\isacharbar}\ Y\ yrhs{\isachardot}\ {\isacharparenleft}Y{\isacharcomma}\ yrhs{\isacharparenright}\ {\isasymin}\ ES{\isacharbraceright}{\isachardoublequoteclose}%
+\begin{isamarkuptext}%
+The computation of regular expressions for equivalent classes is accomplished
+ using a iteration principle given by the following lemma.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{lemma}\isamarkupfalse%
+\ wf{\isacharunderscore}iter\ {\isacharbrackleft}rule{\isacharunderscore}format{\isacharbrackright}{\isacharcolon}\ \isanewline
+\ \ \isakeyword{fixes}\ f\isanewline
+\ \ \isakeyword{assumes}\ step{\isacharcolon}\ {\isachardoublequoteopen}{\isasymAnd}\ e{\isachardot}\ {\isasymlbrakk}P\ e{\isacharsemicolon}\ {\isasymnot}\ Q\ e{\isasymrbrakk}\ {\isasymLongrightarrow}\ {\isacharparenleft}{\isasymexists}\ e{\isacharprime}{\isachardot}\ P\ e{\isacharprime}\ {\isasymand}\ \ {\isacharparenleft}f{\isacharparenleft}e{\isacharprime}{\isacharparenright}{\isacharcomma}\ f{\isacharparenleft}e{\isacharparenright}{\isacharparenright}\ {\isasymin}\ less{\isacharunderscore}than{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{shows}\ pe{\isacharcolon}\ \ \ \ \ {\isachardoublequoteopen}P\ e\ {\isasymlongrightarrow}\ {\isacharparenleft}{\isasymexists}\ e{\isacharprime}{\isachardot}\ P\ e{\isacharprime}\ {\isasymand}\ \ Q\ e{\isacharprime}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+{\isacharparenleft}induct\ e\ rule{\isacharcolon}\ wf{\isacharunderscore}induct\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ {\isacharbrackleft}OF\ wf{\isacharunderscore}inv{\isacharunderscore}image{\isacharbrackleft}OF\ wf{\isacharunderscore}less{\isacharunderscore}than{\isacharcomma}\ \isakeyword{where}\ f\ {\isacharequal}\ {\isachardoublequoteopen}f{\isachardoublequoteclose}{\isacharbrackright}{\isacharbrackright}{\isacharcomma}\ clarify{\isacharparenright}\isanewline
+\ \ \isacommand{fix}\isamarkupfalse%
+\ x\ \isanewline
+\ \ \isacommand{assume}\isamarkupfalse%
+\ h\ {\isacharbrackleft}rule{\isacharunderscore}format{\isacharbrackright}{\isacharcolon}\ \isanewline
+\ \ \ \ {\isachardoublequoteopen}{\isasymforall}y{\isachardot}\ {\isacharparenleft}y{\isacharcomma}\ x{\isacharparenright}\ {\isasymin}\ inv{\isacharunderscore}image\ less{\isacharunderscore}than\ f\ {\isasymlongrightarrow}\ P\ y\ {\isasymlongrightarrow}\ {\isacharparenleft}{\isasymexists}e{\isacharprime}{\isachardot}\ P\ e{\isacharprime}\ {\isasymand}\ Q\ e{\isacharprime}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isakeyword{and}\ px{\isacharcolon}\ {\isachardoublequoteopen}P\ x{\isachardoublequoteclose}\isanewline
+\ \ \isacommand{show}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isasymexists}e{\isacharprime}{\isachardot}\ P\ e{\isacharprime}\ {\isasymand}\ Q\ e{\isacharprime}{\isachardoublequoteclose}\isanewline
+\ \ \isacommand{proof}\isamarkupfalse%
+{\isacharparenleft}cases\ {\isachardoublequoteopen}Q\ x{\isachardoublequoteclose}{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{assume}\isamarkupfalse%
+\ {\isachardoublequoteopen}Q\ x{\isachardoublequoteclose}\ \isacommand{with}\isamarkupfalse%
+\ px\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ blast\isanewline
+\ \ \isacommand{next}\isamarkupfalse%
+\isanewline
+\ \ \ \ \isacommand{assume}\isamarkupfalse%
+\ nq{\isacharcolon}\ {\isachardoublequoteopen}{\isasymnot}\ Q\ x{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{from}\isamarkupfalse%
+\ step\ {\isacharbrackleft}OF\ px\ nq{\isacharbrackright}\isanewline
+\ \ \ \ \isacommand{obtain}\isamarkupfalse%
+\ e{\isacharprime}\ \isakeyword{where}\ pe{\isacharprime}{\isacharcolon}\ {\isachardoublequoteopen}P\ e{\isacharprime}{\isachardoublequoteclose}\ \isakeyword{and}\ ltf{\isacharcolon}\ {\isachardoublequoteopen}{\isacharparenleft}f\ e{\isacharprime}{\isacharcomma}\ f\ x{\isacharparenright}\ {\isasymin}\ less{\isacharunderscore}than{\isachardoublequoteclose}\ \isacommand{by}\isamarkupfalse%
+\ auto\isanewline
+\ \ \ \ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\isanewline
+\ \ \ \ \isacommand{proof}\isamarkupfalse%
+{\isacharparenleft}rule\ h{\isacharparenright}\isanewline
+\ \ \ \ \ \ \isacommand{from}\isamarkupfalse%
+\ ltf\ \isacommand{show}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isacharparenleft}e{\isacharprime}{\isacharcomma}\ x{\isacharparenright}\ {\isasymin}\ inv{\isacharunderscore}image\ less{\isacharunderscore}than\ f{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}simp\ add{\isacharcolon}inv{\isacharunderscore}image{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{next}\isamarkupfalse%
+\isanewline
+\ \ \ \ \ \ \isacommand{from}\isamarkupfalse%
+\ pe{\isacharprime}\ \isacommand{show}\isamarkupfalse%
+\ {\isachardoublequoteopen}P\ e{\isacharprime}{\isachardoublequoteclose}\ \isacommand{{\isachardot}}\isamarkupfalse%
+\isanewline
+\ \ \ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\begin{isamarkuptext}%
+The \isa{P} in lemma \isa{wf{\isacharunderscore}iter} is an invaiant kept throughout the iteration procedure.
+ The particular invariant used to solve our problem is defined by function \isa{Inv{\isacharparenleft}ES{\isacharparenright}},
+ an invariant over equal system \isa{ES}.
+ Every definition starting next till \isa{Inv} stipulates a property to be satisfied by \isa{ES}.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+%
+\begin{isamarkuptext}%
+Every variable is defined at most onece in \isa{ES}.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{definition}\isamarkupfalse%
+\ \isanewline
+\ \ {\isachardoublequoteopen}distinct{\isacharunderscore}equas\ ES\ {\isasymequiv}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ {\isasymforall}\ X\ rhs\ rhs{\isacharprime}{\isachardot}\ {\isacharparenleft}X{\isacharcomma}\ rhs{\isacharparenright}\ {\isasymin}\ ES\ {\isasymand}\ {\isacharparenleft}X{\isacharcomma}\ rhs{\isacharprime}{\isacharparenright}\ {\isasymin}\ ES\ {\isasymlongrightarrow}\ rhs\ {\isacharequal}\ rhs{\isacharprime}{\isachardoublequoteclose}%
+\begin{isamarkuptext}%
+Every equation in \isa{ES} (represented by \isa{{\isacharparenleft}X{\isacharcomma}\ rhs{\isacharparenright}}) is valid, i.e. \isa{{\isacharparenleft}X\ {\isacharequal}\ L\ rhs{\isacharparenright}}.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{definition}\isamarkupfalse%
+\ \isanewline
+\ \ {\isachardoublequoteopen}valid{\isacharunderscore}eqns\ ES\ {\isasymequiv}\ {\isasymforall}\ X\ rhs{\isachardot}\ {\isacharparenleft}X{\isacharcomma}\ rhs{\isacharparenright}\ {\isasymin}\ ES\ {\isasymlongrightarrow}\ {\isacharparenleft}X\ {\isacharequal}\ L\ rhs{\isacharparenright}{\isachardoublequoteclose}%
+\begin{isamarkuptext}%
+\isa{rhs{\isacharunderscore}nonempty\ rhs} requires regular expressions occuring in transitional
+ items of \isa{rhs} does not contain empty string. This is necessary for
+ the application of Arden's transformation to \isa{rhs}.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{definition}\isamarkupfalse%
+\ \isanewline
+\ \ {\isachardoublequoteopen}rhs{\isacharunderscore}nonempty\ rhs\ {\isasymequiv}\ {\isacharparenleft}{\isasymforall}\ Y\ r{\isachardot}\ Trn\ Y\ r\ {\isasymin}\ rhs\ {\isasymlongrightarrow}\ {\isacharbrackleft}{\isacharbrackright}\ {\isasymnotin}\ L\ r{\isacharparenright}{\isachardoublequoteclose}%
+\begin{isamarkuptext}%
+\isa{ardenable\ ES} requires that Arden's transformation is applicable
+ to every equation of equational system \isa{ES}.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{definition}\isamarkupfalse%
+\ \isanewline
+\ \ {\isachardoublequoteopen}ardenable\ ES\ {\isasymequiv}\ {\isasymforall}\ X\ rhs{\isachardot}\ {\isacharparenleft}X{\isacharcomma}\ rhs{\isacharparenright}\ {\isasymin}\ ES\ {\isasymlongrightarrow}\ rhs{\isacharunderscore}nonempty\ rhs{\isachardoublequoteclose}\isanewline
+\isanewline
+\isanewline
+\isacommand{definition}\isamarkupfalse%
+\ \isanewline
+\ \ {\isachardoublequoteopen}non{\isacharunderscore}empty\ ES\ {\isasymequiv}\ {\isasymforall}\ X\ rhs{\isachardot}\ {\isacharparenleft}X{\isacharcomma}\ rhs{\isacharparenright}\ {\isasymin}\ ES\ {\isasymlongrightarrow}\ X\ {\isasymnoteq}\ {\isacharbraceleft}{\isacharbraceright}{\isachardoublequoteclose}%
+\begin{isamarkuptext}%
+The following \isa{finite{\isacharunderscore}rhs\ ES} requires every equation in \isa{rhs} be finite.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{definition}\isamarkupfalse%
+\isanewline
+\ \ {\isachardoublequoteopen}finite{\isacharunderscore}rhs\ ES\ {\isasymequiv}\ {\isasymforall}\ X\ rhs{\isachardot}\ {\isacharparenleft}X{\isacharcomma}\ rhs{\isacharparenright}\ {\isasymin}\ ES\ {\isasymlongrightarrow}\ finite\ rhs{\isachardoublequoteclose}%
+\begin{isamarkuptext}%
+The following \isa{classes{\isacharunderscore}of\ rhs} returns all variables (or equivalent classes)
+ occuring in \isa{rhs}.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{definition}\isamarkupfalse%
+\ \isanewline
+\ \ {\isachardoublequoteopen}classes{\isacharunderscore}of\ rhs\ {\isasymequiv}\ {\isacharbraceleft}X{\isachardot}\ {\isasymexists}\ r{\isachardot}\ Trn\ X\ r\ {\isasymin}\ rhs{\isacharbraceright}{\isachardoublequoteclose}%
+\begin{isamarkuptext}%
+The following \isa{lefts{\isacharunderscore}of\ ES} returns all variables
+ defined by equational system \isa{ES}.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{definition}\isamarkupfalse%
+\isanewline
+\ \ {\isachardoublequoteopen}lefts{\isacharunderscore}of\ ES\ {\isasymequiv}\ {\isacharbraceleft}Y\ {\isacharbar}\ Y\ yrhs{\isachardot}\ {\isacharparenleft}Y{\isacharcomma}\ yrhs{\isacharparenright}\ {\isasymin}\ ES{\isacharbraceright}{\isachardoublequoteclose}%
+\begin{isamarkuptext}%
+The following \isa{self{\isacharunderscore}contained\ ES} requires that every
+ variable occuring on the right hand side of equations is already defined by some
+ equation in \isa{ES}.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{definition}\isamarkupfalse%
+\ \isanewline
+\ \ {\isachardoublequoteopen}self{\isacharunderscore}contained\ ES\ {\isasymequiv}\ {\isasymforall}\ {\isacharparenleft}X{\isacharcomma}\ xrhs{\isacharparenright}\ {\isasymin}\ ES{\isachardot}\ classes{\isacharunderscore}of\ xrhs\ {\isasymsubseteq}\ lefts{\isacharunderscore}of\ ES{\isachardoublequoteclose}%
+\begin{isamarkuptext}%
+The invariant \isa{Inv{\isacharparenleft}ES{\isacharparenright}} is obtained by conjunctioning all the previous
+ defined constaints on \isa{ES}.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{definition}\isamarkupfalse%
+\ \isanewline
+\ \ {\isachardoublequoteopen}Inv\ ES\ {\isasymequiv}\ valid{\isacharunderscore}eqns\ ES\ {\isasymand}\ finite\ ES\ {\isasymand}\ distinct{\isacharunderscore}equas\ ES\ {\isasymand}\ ardenable\ ES\ {\isasymand}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ non{\isacharunderscore}empty\ ES\ {\isasymand}\ finite{\isacharunderscore}rhs\ ES\ {\isasymand}\ self{\isacharunderscore}contained\ ES{\isachardoublequoteclose}%
+\isamarkupsubsection{Proof for this direction%
+}
+\isamarkuptrue%
+%
+\begin{isamarkuptext}%
+The following are some basic properties of the above definitions.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{lemma}\isamarkupfalse%
+\ L{\isacharunderscore}rhs{\isacharunderscore}union{\isacharunderscore}distrib{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}\ L\ {\isacharparenleft}A{\isacharcolon}{\isacharcolon}rhs{\isacharunderscore}item\ set{\isacharparenright}\ {\isasymunion}\ L\ B\ {\isacharequal}\ L\ {\isacharparenleft}A\ {\isasymunion}\ B{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ simp%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ finite{\isacharunderscore}snd{\isacharunderscore}Trn{\isacharcolon}\isanewline
+\ \ \isakeyword{assumes}\ finite{\isacharcolon}{\isachardoublequoteopen}finite\ rhs{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{shows}\ {\isachardoublequoteopen}finite\ {\isacharbraceleft}r\isactrlisub {\isadigit{2}}{\isachardot}\ Trn\ Y\ r\isactrlisub {\isadigit{2}}\ {\isasymin}\ rhs{\isacharbraceright}{\isachardoublequoteclose}\ {\isacharparenleft}\isakeyword{is}\ {\isachardoublequoteopen}finite\ {\isacharquery}B{\isachardoublequoteclose}{\isacharparenright}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+{\isacharminus}\isanewline
+\ \ \isacommand{def}\isamarkupfalse%
+\ rhs{\isacharprime}\ {\isasymequiv}\ {\isachardoublequoteopen}{\isacharbraceleft}e\ {\isasymin}\ rhs{\isachardot}\ {\isasymexists}\ r{\isachardot}\ e\ {\isacharequal}\ Trn\ Y\ r{\isacharbraceright}{\isachardoublequoteclose}\isanewline
+\ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isacharquery}B\ {\isacharequal}\ {\isacharparenleft}snd\ o\ the{\isacharunderscore}Trn{\isacharparenright}\ {\isacharbackquote}\ rhs{\isacharprime}{\isachardoublequoteclose}\ \isacommand{using}\isamarkupfalse%
+\ rhs{\isacharprime}{\isacharunderscore}def\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}image{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \isacommand{moreover}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}finite\ rhs{\isacharprime}{\isachardoublequoteclose}\ \isacommand{using}\isamarkupfalse%
+\ finite\ rhs{\isacharprime}{\isacharunderscore}def\ \isacommand{by}\isamarkupfalse%
+\ auto\isanewline
+\ \ \isacommand{ultimately}\isamarkupfalse%
+\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ simp\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ rexp{\isacharunderscore}of{\isacharunderscore}empty{\isacharcolon}\isanewline
+\ \ \isakeyword{assumes}\ finite{\isacharcolon}{\isachardoublequoteopen}finite\ rhs{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{and}\ nonempty{\isacharcolon}{\isachardoublequoteopen}rhs{\isacharunderscore}nonempty\ rhs{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{shows}\ {\isachardoublequoteopen}{\isacharbrackleft}{\isacharbrackright}\ {\isasymnotin}\ L\ {\isacharparenleft}rexp{\isacharunderscore}of\ rhs\ X{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{using}\isamarkupfalse%
+\ finite\ nonempty\ rhs{\isacharunderscore}nonempty{\isacharunderscore}def\isanewline
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}drule{\isacharunderscore}tac\ finite{\isacharunderscore}snd{\isacharunderscore}Trn{\isacharbrackleft}\isakeyword{where}\ Y\ {\isacharequal}\ X{\isacharbrackright}{\isacharcomma}\ auto\ simp{\isacharcolon}rexp{\isacharunderscore}of{\isacharunderscore}def\ items{\isacharunderscore}of{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ {\isacharbrackleft}intro{\isacharbang}{\isacharbrackright}{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}P\ {\isacharparenleft}Trn\ X\ r{\isacharparenright}\ {\isasymLongrightarrow}\ {\isacharparenleft}{\isasymexists}a{\isachardot}\ {\isacharparenleft}{\isasymexists}r{\isachardot}\ a\ {\isacharequal}\ Trn\ X\ r\ {\isasymand}\ P\ a{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}%
+\isadelimproof
+\ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ auto%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+%
+\endisadelimproof
+\isanewline
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ finite{\isacharunderscore}items{\isacharunderscore}of{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}finite\ rhs\ {\isasymLongrightarrow}\ finite\ {\isacharparenleft}items{\isacharunderscore}of\ rhs\ X{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}items{\isacharunderscore}of{\isacharunderscore}def\ intro{\isacharcolon}finite{\isacharunderscore}subset{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ lang{\isacharunderscore}of{\isacharunderscore}rexp{\isacharunderscore}of{\isacharcolon}\isanewline
+\ \ \isakeyword{assumes}\ finite{\isacharcolon}{\isachardoublequoteopen}finite\ rhs{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{shows}\ {\isachardoublequoteopen}L\ {\isacharparenleft}items{\isacharunderscore}of\ rhs\ X{\isacharparenright}\ {\isacharequal}\ X\ {\isacharsemicolon}{\isacharsemicolon}\ {\isacharparenleft}L\ {\isacharparenleft}rexp{\isacharunderscore}of\ rhs\ X{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+\ {\isacharminus}\isanewline
+\ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}finite\ {\isacharparenleft}{\isacharparenleft}snd\ {\isasymcirc}\ the{\isacharunderscore}Trn{\isacharparenright}\ {\isacharbackquote}\ items{\isacharunderscore}of\ rhs\ X{\isacharparenright}{\isachardoublequoteclose}\ \isacommand{using}\isamarkupfalse%
+\ finite{\isacharunderscore}items{\isacharunderscore}of{\isacharbrackleft}OF\ finite{\isacharbrackright}\ \isacommand{by}\isamarkupfalse%
+\ auto\isanewline
+\ \ \isacommand{thus}\isamarkupfalse%
+\ {\isacharquery}thesis\isanewline
+\ \ \ \ \isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}rexp{\isacharunderscore}of{\isacharunderscore}def\ Seq{\isacharunderscore}def\ items{\isacharunderscore}of{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}rule{\isacharunderscore}tac\ x\ {\isacharequal}\ s{\isadigit{1}}\ \isakeyword{in}\ exI{\isacharcomma}\ rule{\isacharunderscore}tac\ x\ {\isacharequal}\ s{\isadigit{2}}\ \isakeyword{in}\ exI{\isacharcomma}\ auto{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}rule{\isacharunderscore}tac\ x{\isacharequal}\ {\isachardoublequoteopen}Trn\ X\ r{\isachardoublequoteclose}\ \isakeyword{in}\ exI{\isacharcomma}\ auto\ simp{\isacharcolon}Seq{\isacharunderscore}def{\isacharparenright}\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ rexp{\isacharunderscore}of{\isacharunderscore}lam{\isacharunderscore}eq{\isacharunderscore}lam{\isacharunderscore}set{\isacharcolon}\isanewline
+\ \ \isakeyword{assumes}\ finite{\isacharcolon}\ {\isachardoublequoteopen}finite\ rhs{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{shows}\ {\isachardoublequoteopen}L\ {\isacharparenleft}rexp{\isacharunderscore}of{\isacharunderscore}lam\ rhs{\isacharparenright}\ {\isacharequal}\ L\ {\isacharparenleft}lam{\isacharunderscore}of\ rhs{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+\ {\isacharminus}\isanewline
+\ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}finite\ {\isacharparenleft}the{\isacharunderscore}r\ {\isacharbackquote}\ {\isacharbraceleft}Lam\ r\ {\isacharbar}r{\isachardot}\ Lam\ r\ {\isasymin}\ rhs{\isacharbraceright}{\isacharparenright}{\isachardoublequoteclose}\ \isacommand{using}\isamarkupfalse%
+\ finite\isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}rule{\isacharunderscore}tac\ finite{\isacharunderscore}imageI{\isacharcomma}\ auto\ intro{\isacharcolon}finite{\isacharunderscore}subset{\isacharparenright}\isanewline
+\ \ \isacommand{thus}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}rexp{\isacharunderscore}of{\isacharunderscore}lam{\isacharunderscore}def\ lam{\isacharunderscore}of{\isacharunderscore}def{\isacharparenright}\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ {\isacharbrackleft}simp{\isacharbrackright}{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}\ L\ {\isacharparenleft}attach{\isacharunderscore}rexp\ r\ xb{\isacharparenright}\ {\isacharequal}\ L\ xb\ {\isacharsemicolon}{\isacharsemicolon}\ L\ r{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}cases\ xb{\isacharcomma}\ auto\ simp{\isacharcolon}Seq{\isacharunderscore}def{\isacharparenright}\isanewline
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}rule{\isacharunderscore}tac\ x\ {\isacharequal}\ {\isachardoublequoteopen}s{\isadigit{1}}\ {\isacharat}\ s{\isadigit{1}}a{\isachardoublequoteclose}\ \isakeyword{in}\ exI{\isacharcomma}\ rule{\isacharunderscore}tac\ x\ {\isacharequal}\ s{\isadigit{2}}a\ \isakeyword{in}\ exI{\isacharcomma}auto\ simp{\isacharcolon}Seq{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ lang{\isacharunderscore}of{\isacharunderscore}append{\isacharunderscore}rhs{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}L\ {\isacharparenleft}append{\isacharunderscore}rhs{\isacharunderscore}rexp\ rhs\ r{\isacharparenright}\ {\isacharequal}\ L\ rhs\ {\isacharsemicolon}{\isacharsemicolon}\ L\ r{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}append{\isacharunderscore}rhs{\isacharunderscore}rexp{\isacharunderscore}def\ image{\isacharunderscore}def{\isacharparenright}\isanewline
+\isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}Seq{\isacharunderscore}def{\isacharparenright}\isanewline
+\isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}rule{\isacharunderscore}tac\ x\ {\isacharequal}\ {\isachardoublequoteopen}L\ xb\ {\isacharsemicolon}{\isacharsemicolon}\ L\ r{\isachardoublequoteclose}\ \isakeyword{in}\ exI{\isacharcomma}\ auto\ simp\ add{\isacharcolon}Seq{\isacharunderscore}def{\isacharparenright}\isanewline
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}rule{\isacharunderscore}tac\ x\ {\isacharequal}\ {\isachardoublequoteopen}attach{\isacharunderscore}rexp\ r\ xb{\isachardoublequoteclose}\ \isakeyword{in}\ exI{\isacharcomma}\ auto\ simp{\isacharcolon}Seq{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ classes{\isacharunderscore}of{\isacharunderscore}union{\isacharunderscore}distrib{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}classes{\isacharunderscore}of\ A\ {\isasymunion}\ classes{\isacharunderscore}of\ B\ {\isacharequal}\ classes{\isacharunderscore}of\ {\isacharparenleft}A\ {\isasymunion}\ B{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp\ add{\isacharcolon}classes{\isacharunderscore}of{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ lefts{\isacharunderscore}of{\isacharunderscore}union{\isacharunderscore}distrib{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}lefts{\isacharunderscore}of\ A\ {\isasymunion}\ lefts{\isacharunderscore}of\ B\ {\isacharequal}\ lefts{\isacharunderscore}of\ {\isacharparenleft}A\ {\isasymunion}\ B{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}lefts{\isacharunderscore}of{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\begin{isamarkuptext}%
+The following several lemmas until \isa{init{\isacharunderscore}ES{\isacharunderscore}satisfy{\isacharunderscore}Inv} are
+ to prove that initial equational system satisfies invariant \isa{Inv}.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{lemma}\isamarkupfalse%
+\ defined{\isacharunderscore}by{\isacharunderscore}str{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}{\isasymlbrakk}s\ {\isasymin}\ X{\isacharsemicolon}\ X\ {\isasymin}\ UNIV\ {\isacharslash}{\isacharslash}\ {\isacharparenleft}{\isasymapprox}Lang{\isacharparenright}{\isasymrbrakk}\ {\isasymLongrightarrow}\ X\ {\isacharequal}\ {\isacharparenleft}{\isasymapprox}Lang{\isacharparenright}\ {\isacharbackquote}{\isacharbackquote}\ {\isacharbraceleft}s{\isacharbraceright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}quotient{\isacharunderscore}def\ Image{\isacharunderscore}def\ str{\isacharunderscore}eq{\isacharunderscore}rel{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ every{\isacharunderscore}eqclass{\isacharunderscore}has{\isacharunderscore}transition{\isacharcolon}\isanewline
+\ \ \isakeyword{assumes}\ has{\isacharunderscore}str{\isacharcolon}\ {\isachardoublequoteopen}s\ {\isacharat}\ {\isacharbrackleft}c{\isacharbrackright}\ {\isasymin}\ X{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{and}\ \ \ \ \ in{\isacharunderscore}CS{\isacharcolon}\ \ \ {\isachardoublequoteopen}X\ {\isasymin}\ UNIV\ {\isacharslash}{\isacharslash}\ {\isacharparenleft}{\isasymapprox}Lang{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{obtains}\ Y\ \isakeyword{where}\ {\isachardoublequoteopen}Y\ {\isasymin}\ UNIV\ {\isacharslash}{\isacharslash}\ {\isacharparenleft}{\isasymapprox}Lang{\isacharparenright}{\isachardoublequoteclose}\ \isakeyword{and}\ {\isachardoublequoteopen}Y\ {\isacharsemicolon}{\isacharsemicolon}\ {\isacharbraceleft}{\isacharbrackleft}c{\isacharbrackright}{\isacharbraceright}\ {\isasymsubseteq}\ X{\isachardoublequoteclose}\ \isakeyword{and}\ {\isachardoublequoteopen}s\ {\isasymin}\ Y{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+\ {\isacharminus}\isanewline
+\ \ \isacommand{def}\isamarkupfalse%
+\ Y\ {\isasymequiv}\ {\isachardoublequoteopen}{\isacharparenleft}{\isasymapprox}Lang{\isacharparenright}\ {\isacharbackquote}{\isacharbackquote}\ {\isacharbraceleft}s{\isacharbraceright}{\isachardoublequoteclose}\isanewline
+\ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}Y\ {\isasymin}\ UNIV\ {\isacharslash}{\isacharslash}\ {\isacharparenleft}{\isasymapprox}Lang{\isacharparenright}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \isacommand{unfolding}\isamarkupfalse%
+\ Y{\isacharunderscore}def\ quotient{\isacharunderscore}def\ \isacommand{by}\isamarkupfalse%
+\ auto\isanewline
+\ \ \isacommand{moreover}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}X\ {\isacharequal}\ {\isacharparenleft}{\isasymapprox}Lang{\isacharparenright}\ {\isacharbackquote}{\isacharbackquote}\ {\isacharbraceleft}s\ {\isacharat}\ {\isacharbrackleft}c{\isacharbrackright}{\isacharbraceright}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \isacommand{using}\isamarkupfalse%
+\ has{\isacharunderscore}str\ in{\isacharunderscore}CS\ defined{\isacharunderscore}by{\isacharunderscore}str\ \isacommand{by}\isamarkupfalse%
+\ blast\isanewline
+\ \ \isacommand{then}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}Y\ {\isacharsemicolon}{\isacharsemicolon}\ {\isacharbraceleft}{\isacharbrackleft}c{\isacharbrackright}{\isacharbraceright}\ {\isasymsubseteq}\ X{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \isacommand{unfolding}\isamarkupfalse%
+\ Y{\isacharunderscore}def\ Image{\isacharunderscore}def\ Seq{\isacharunderscore}def\isanewline
+\ \ \ \ \isacommand{unfolding}\isamarkupfalse%
+\ str{\isacharunderscore}eq{\isacharunderscore}rel{\isacharunderscore}def\isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ clarsimp\isanewline
+\ \ \isacommand{moreover}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}s\ {\isasymin}\ Y{\isachardoublequoteclose}\ \isacommand{unfolding}\isamarkupfalse%
+\ Y{\isacharunderscore}def\ \isanewline
+\ \ \ \ \isacommand{unfolding}\isamarkupfalse%
+\ Image{\isacharunderscore}def\ str{\isacharunderscore}eq{\isacharunderscore}rel{\isacharunderscore}def\ \isacommand{by}\isamarkupfalse%
+\ simp\isanewline
+\ \ \isacommand{ultimately}\isamarkupfalse%
+\ \isacommand{show}\isamarkupfalse%
+\ thesis\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}blast\ intro{\isacharcolon}\ that{\isacharparenright}\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ l{\isacharunderscore}eq{\isacharunderscore}r{\isacharunderscore}in{\isacharunderscore}eqs{\isacharcolon}\isanewline
+\ \ \isakeyword{assumes}\ X{\isacharunderscore}in{\isacharunderscore}eqs{\isacharcolon}\ {\isachardoublequoteopen}{\isacharparenleft}X{\isacharcomma}\ xrhs{\isacharparenright}\ {\isasymin}\ {\isacharparenleft}eqs\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isacharparenleft}{\isasymapprox}Lang{\isacharparenright}{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{shows}\ {\isachardoublequoteopen}X\ {\isacharequal}\ L\ xrhs{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+\ \isanewline
+\ \ \isacommand{show}\isamarkupfalse%
+\ {\isachardoublequoteopen}X\ {\isasymsubseteq}\ L\ xrhs{\isachardoublequoteclose}\isanewline
+\ \ \isacommand{proof}\isamarkupfalse%
+\isanewline
+\ \ \ \ \isacommand{fix}\isamarkupfalse%
+\ x\isanewline
+\ \ \ \ \isacommand{assume}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isacharparenleft}{\isadigit{1}}{\isacharparenright}{\isachardoublequoteclose}{\isacharcolon}\ {\isachardoublequoteopen}x\ {\isasymin}\ X{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{show}\isamarkupfalse%
+\ {\isachardoublequoteopen}x\ {\isasymin}\ L\ xrhs{\isachardoublequoteclose}\ \ \ \ \ \ \ \ \ \ \isanewline
+\ \ \ \ \isacommand{proof}\isamarkupfalse%
+\ {\isacharparenleft}cases\ {\isachardoublequoteopen}x\ {\isacharequal}\ {\isacharbrackleft}{\isacharbrackright}{\isachardoublequoteclose}{\isacharparenright}\isanewline
+\ \ \ \ \ \ \isacommand{assume}\isamarkupfalse%
+\ empty{\isacharcolon}\ {\isachardoublequoteopen}x\ {\isacharequal}\ {\isacharbrackleft}{\isacharbrackright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \isacommand{thus}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{using}\isamarkupfalse%
+\ X{\isacharunderscore}in{\isacharunderscore}eqs\ {\isachardoublequoteopen}{\isacharparenleft}{\isadigit{1}}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}eqs{\isacharunderscore}def\ init{\isacharunderscore}rhs{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{next}\isamarkupfalse%
+\isanewline
+\ \ \ \ \ \ \isacommand{assume}\isamarkupfalse%
+\ not{\isacharunderscore}empty{\isacharcolon}\ {\isachardoublequoteopen}x\ {\isasymnoteq}\ {\isacharbrackleft}{\isacharbrackright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \isacommand{then}\isamarkupfalse%
+\ \isacommand{obtain}\isamarkupfalse%
+\ clist\ c\ \isakeyword{where}\ decom{\isacharcolon}\ {\isachardoublequoteopen}x\ {\isacharequal}\ clist\ {\isacharat}\ {\isacharbrackleft}c{\isacharbrackright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}case{\isacharunderscore}tac\ x\ rule{\isacharcolon}rev{\isacharunderscore}cases{\isacharcomma}\ auto{\isacharparenright}\isanewline
+\ \ \ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}X\ {\isasymin}\ UNIV\ {\isacharslash}{\isacharslash}\ {\isacharparenleft}{\isasymapprox}Lang{\isacharparenright}{\isachardoublequoteclose}\ \isacommand{using}\isamarkupfalse%
+\ X{\isacharunderscore}in{\isacharunderscore}eqs\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}eqs{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \ \ \ \ \isacommand{then}\isamarkupfalse%
+\ \isacommand{obtain}\isamarkupfalse%
+\ Y\ \isanewline
+\ \ \ \ \ \ \ \ \isakeyword{where}\ {\isachardoublequoteopen}Y\ {\isasymin}\ UNIV\ {\isacharslash}{\isacharslash}\ {\isacharparenleft}{\isasymapprox}Lang{\isacharparenright}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \ \ \ \ \isakeyword{and}\ {\isachardoublequoteopen}Y\ {\isacharsemicolon}{\isacharsemicolon}\ {\isacharbraceleft}{\isacharbrackleft}c{\isacharbrackright}{\isacharbraceright}\ {\isasymsubseteq}\ X{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \ \ \isakeyword{and}\ {\isachardoublequoteopen}clist\ {\isasymin}\ Y{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \ \ \isacommand{using}\isamarkupfalse%
+\ decom\ {\isachardoublequoteopen}{\isacharparenleft}{\isadigit{1}}{\isacharparenright}{\isachardoublequoteclose}\ every{\isacharunderscore}eqclass{\isacharunderscore}has{\isacharunderscore}transition\ \isacommand{by}\isamarkupfalse%
+\ blast\isanewline
+\ \ \ \ \ \ \isacommand{hence}\isamarkupfalse%
+\ \isanewline
+\ \ \ \ \ \ \ \ {\isachardoublequoteopen}x\ {\isasymin}\ L\ {\isacharbraceleft}Trn\ Y\ {\isacharparenleft}CHAR\ c{\isacharparenright}{\isacharbar}\ Y\ c{\isachardot}\ Y\ {\isasymin}\ UNIV\ {\isacharslash}{\isacharslash}\ {\isacharparenleft}{\isasymapprox}Lang{\isacharparenright}\ {\isasymand}\ Y\ {\isacharsemicolon}{\isacharsemicolon}\ {\isacharbraceleft}{\isacharbrackleft}c{\isacharbrackright}{\isacharbraceright}\ {\isasymsubseteq}\ X{\isacharbraceright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \ \ \isacommand{using}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isacharparenleft}{\isadigit{1}}{\isacharparenright}{\isachardoublequoteclose}\ decom\isanewline
+\ \ \ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}simp{\isacharcomma}\ rule{\isacharunderscore}tac\ x\ {\isacharequal}\ {\isachardoublequoteopen}Trn\ Y\ {\isacharparenleft}CHAR\ c{\isacharparenright}{\isachardoublequoteclose}\ \isakeyword{in}\ exI{\isacharcomma}\ simp\ add{\isacharcolon}Seq{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \ \ \ \ \isacommand{thus}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{using}\isamarkupfalse%
+\ X{\isacharunderscore}in{\isacharunderscore}eqs\ {\isachardoublequoteopen}{\isacharparenleft}{\isadigit{1}}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}simp\ add{\isacharcolon}eqs{\isacharunderscore}def\ init{\isacharunderscore}rhs{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\isacommand{next}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{show}\isamarkupfalse%
+\ {\isachardoublequoteopen}L\ xrhs\ {\isasymsubseteq}\ X{\isachardoublequoteclose}\ \isacommand{using}\isamarkupfalse%
+\ X{\isacharunderscore}in{\isacharunderscore}eqs\isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}eqs{\isacharunderscore}def\ init{\isacharunderscore}rhs{\isacharunderscore}def{\isacharparenright}\ \isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ finite{\isacharunderscore}init{\isacharunderscore}rhs{\isacharcolon}\ \isanewline
+\ \ \isakeyword{assumes}\ finite{\isacharcolon}\ {\isachardoublequoteopen}finite\ CS{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{shows}\ {\isachardoublequoteopen}finite\ {\isacharparenleft}init{\isacharunderscore}rhs\ CS\ X{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+{\isacharminus}\isanewline
+\ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}finite\ {\isacharbraceleft}Trn\ Y\ {\isacharparenleft}CHAR\ c{\isacharparenright}\ {\isacharbar}Y\ c{\isachardot}\ Y\ {\isasymin}\ CS\ {\isasymand}\ Y\ {\isacharsemicolon}{\isacharsemicolon}\ {\isacharbraceleft}{\isacharbrackleft}c{\isacharbrackright}{\isacharbraceright}\ {\isasymsubseteq}\ X{\isacharbraceright}{\isachardoublequoteclose}\ {\isacharparenleft}\isakeyword{is}\ {\isachardoublequoteopen}finite\ {\isacharquery}A{\isachardoublequoteclose}{\isacharparenright}\isanewline
+\ \ \isacommand{proof}\isamarkupfalse%
+\ {\isacharminus}\isanewline
+\ \ \ \ \isacommand{def}\isamarkupfalse%
+\ S\ {\isasymequiv}\ {\isachardoublequoteopen}{\isacharbraceleft}{\isacharparenleft}Y{\isacharcomma}\ c{\isacharparenright}{\isacharbar}\ Y\ c{\isachardot}\ Y\ {\isasymin}\ CS\ {\isasymand}\ Y\ {\isacharsemicolon}{\isacharsemicolon}\ {\isacharbraceleft}{\isacharbrackleft}c{\isacharbrackright}{\isacharbraceright}\ {\isasymsubseteq}\ X{\isacharbraceright}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \isacommand{def}\isamarkupfalse%
+\ h\ {\isasymequiv}\ {\isachardoublequoteopen}{\isasymlambda}\ {\isacharparenleft}Y{\isacharcomma}\ c{\isacharparenright}{\isachardot}\ Trn\ Y\ {\isacharparenleft}CHAR\ c{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}finite\ {\isacharparenleft}CS\ {\isasymtimes}\ {\isacharparenleft}UNIV{\isacharcolon}{\isacharcolon}char\ set{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\ \isacommand{using}\isamarkupfalse%
+\ finite\ \isacommand{by}\isamarkupfalse%
+\ auto\isanewline
+\ \ \ \ \isacommand{hence}\isamarkupfalse%
+\ {\isachardoublequoteopen}finite\ S{\isachardoublequoteclose}\ \isacommand{using}\isamarkupfalse%
+\ S{\isacharunderscore}def\ \isanewline
+\ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}rule{\isacharunderscore}tac\ B\ {\isacharequal}\ {\isachardoublequoteopen}CS\ {\isasymtimes}\ UNIV{\isachardoublequoteclose}\ \isakeyword{in}\ finite{\isacharunderscore}subset{\isacharcomma}\ auto{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{moreover}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isacharquery}A\ {\isacharequal}\ h\ {\isacharbackquote}\ S{\isachardoublequoteclose}\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}\ S{\isacharunderscore}def\ h{\isacharunderscore}def\ image{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{ultimately}\isamarkupfalse%
+\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isanewline
+\ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ auto\isanewline
+\ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{thus}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}simp\ add{\isacharcolon}init{\isacharunderscore}rhs{\isacharunderscore}def{\isacharparenright}\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ init{\isacharunderscore}ES{\isacharunderscore}satisfy{\isacharunderscore}Inv{\isacharcolon}\isanewline
+\ \ \isakeyword{assumes}\ finite{\isacharunderscore}CS{\isacharcolon}\ {\isachardoublequoteopen}finite\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isacharparenleft}{\isasymapprox}Lang{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{shows}\ {\isachardoublequoteopen}Inv\ {\isacharparenleft}eqs\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isacharparenleft}{\isasymapprox}Lang{\isacharparenright}{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+\ {\isacharminus}\isanewline
+\ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}finite\ {\isacharparenleft}eqs\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isacharparenleft}{\isasymapprox}Lang{\isacharparenright}{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\ \isacommand{using}\isamarkupfalse%
+\ finite{\isacharunderscore}CS\isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}simp\ add{\isacharcolon}eqs{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \isacommand{moreover}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}distinct{\isacharunderscore}equas\ {\isacharparenleft}eqs\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isacharparenleft}{\isasymapprox}Lang{\isacharparenright}{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\ \ \ \ \ \isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}simp\ add{\isacharcolon}distinct{\isacharunderscore}equas{\isacharunderscore}def\ eqs{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \isacommand{moreover}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}ardenable\ {\isacharparenleft}eqs\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isacharparenleft}{\isasymapprox}Lang{\isacharparenright}{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp\ add{\isacharcolon}ardenable{\isacharunderscore}def\ eqs{\isacharunderscore}def\ init{\isacharunderscore}rhs{\isacharunderscore}def\ rhs{\isacharunderscore}nonempty{\isacharunderscore}def\ del{\isacharcolon}L{\isacharunderscore}rhs{\isachardot}simps{\isacharparenright}\isanewline
+\ \ \isacommand{moreover}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}valid{\isacharunderscore}eqns\ {\isacharparenleft}eqs\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isacharparenleft}{\isasymapprox}Lang{\isacharparenright}{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{using}\isamarkupfalse%
+\ l{\isacharunderscore}eq{\isacharunderscore}r{\isacharunderscore}in{\isacharunderscore}eqs\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}simp\ add{\isacharcolon}valid{\isacharunderscore}eqns{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \isacommand{moreover}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}non{\isacharunderscore}empty\ {\isacharparenleft}eqs\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isacharparenleft}{\isasymapprox}Lang{\isacharparenright}{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}non{\isacharunderscore}empty{\isacharunderscore}def\ eqs{\isacharunderscore}def\ quotient{\isacharunderscore}def\ Image{\isacharunderscore}def\ str{\isacharunderscore}eq{\isacharunderscore}rel{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \isacommand{moreover}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}finite{\isacharunderscore}rhs\ {\isacharparenleft}eqs\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isacharparenleft}{\isasymapprox}Lang{\isacharparenright}{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{using}\isamarkupfalse%
+\ finite{\isacharunderscore}init{\isacharunderscore}rhs{\isacharbrackleft}OF\ finite{\isacharunderscore}CS{\isacharbrackright}\ \isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}finite{\isacharunderscore}rhs{\isacharunderscore}def\ eqs{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \isacommand{moreover}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}self{\isacharunderscore}contained\ {\isacharparenleft}eqs\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isacharparenleft}{\isasymapprox}Lang{\isacharparenright}{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}self{\isacharunderscore}contained{\isacharunderscore}def\ eqs{\isacharunderscore}def\ init{\isacharunderscore}rhs{\isacharunderscore}def\ classes{\isacharunderscore}of{\isacharunderscore}def\ lefts{\isacharunderscore}of{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \isacommand{ultimately}\isamarkupfalse%
+\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}simp\ add{\isacharcolon}Inv{\isacharunderscore}def{\isacharparenright}\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\begin{isamarkuptext}%
+From this point until \isa{iteration{\isacharunderscore}step}, we are trying to prove
+ that there exists iteration steps which keep \isa{Inv{\isacharparenleft}ES{\isacharparenright}} while
+ decreasing the size of \isa{ES} with every iteration.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{lemma}\isamarkupfalse%
+\ arden{\isacharunderscore}variate{\isacharunderscore}keeps{\isacharunderscore}eq{\isacharcolon}\isanewline
+\ \ \isakeyword{assumes}\ l{\isacharunderscore}eq{\isacharunderscore}r{\isacharcolon}\ {\isachardoublequoteopen}X\ {\isacharequal}\ L\ rhs{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{and}\ not{\isacharunderscore}empty{\isacharcolon}\ {\isachardoublequoteopen}{\isacharbrackleft}{\isacharbrackright}\ {\isasymnotin}\ L\ {\isacharparenleft}rexp{\isacharunderscore}of\ rhs\ X{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{and}\ finite{\isacharcolon}\ {\isachardoublequoteopen}finite\ rhs{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{shows}\ {\isachardoublequoteopen}X\ {\isacharequal}\ L\ {\isacharparenleft}arden{\isacharunderscore}variate\ X\ rhs{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+\ {\isacharminus}\isanewline
+\ \ \isacommand{def}\isamarkupfalse%
+\ A\ {\isasymequiv}\ {\isachardoublequoteopen}L\ {\isacharparenleft}rexp{\isacharunderscore}of\ rhs\ X{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \isacommand{def}\isamarkupfalse%
+\ b\ {\isasymequiv}\ {\isachardoublequoteopen}rhs\ {\isacharminus}\ items{\isacharunderscore}of\ rhs\ X{\isachardoublequoteclose}\isanewline
+\ \ \isacommand{def}\isamarkupfalse%
+\ B\ {\isasymequiv}\ {\isachardoublequoteopen}L\ b{\isachardoublequoteclose}\ \isanewline
+\ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}X\ {\isacharequal}\ B\ {\isacharsemicolon}{\isacharsemicolon}\ A{\isasymstar}{\isachardoublequoteclose}\isanewline
+\ \ \isacommand{proof}\isamarkupfalse%
+{\isacharminus}\isanewline
+\ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}rhs\ {\isacharequal}\ items{\isacharunderscore}of\ rhs\ X\ {\isasymunion}\ b{\isachardoublequoteclose}\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}b{\isacharunderscore}def\ items{\isacharunderscore}of{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{hence}\isamarkupfalse%
+\ {\isachardoublequoteopen}L\ rhs\ {\isacharequal}\ L{\isacharparenleft}items{\isacharunderscore}of\ rhs\ X\ {\isasymunion}\ b{\isacharparenright}{\isachardoublequoteclose}\ \isacommand{by}\isamarkupfalse%
+\ simp\isanewline
+\ \ \ \ \isacommand{hence}\isamarkupfalse%
+\ {\isachardoublequoteopen}L\ rhs\ {\isacharequal}\ L{\isacharparenleft}items{\isacharunderscore}of\ rhs\ X{\isacharparenright}\ {\isasymunion}\ B{\isachardoublequoteclose}\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}simp\ only{\isacharcolon}L{\isacharunderscore}rhs{\isacharunderscore}union{\isacharunderscore}distrib\ B{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{with}\isamarkupfalse%
+\ lang{\isacharunderscore}of{\isacharunderscore}rexp{\isacharunderscore}of\isanewline
+\ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}L\ rhs\ {\isacharequal}\ X\ {\isacharsemicolon}{\isacharsemicolon}\ A\ {\isasymunion}\ B\ {\isachardoublequoteclose}\ \isacommand{using}\isamarkupfalse%
+\ finite\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}simp\ only{\isacharcolon}B{\isacharunderscore}def\ b{\isacharunderscore}def\ A{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{thus}\isamarkupfalse%
+\ {\isacharquery}thesis\isanewline
+\ \ \ \ \ \ \isacommand{using}\isamarkupfalse%
+\ l{\isacharunderscore}eq{\isacharunderscore}r\ not{\isacharunderscore}empty\isanewline
+\ \ \ \ \ \ \isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}drule{\isacharunderscore}tac\ B\ {\isacharequal}\ B\ \isakeyword{and}\ X\ {\isacharequal}\ X\ \isakeyword{in}\ ardens{\isacharunderscore}revised{\isacharparenright}\isanewline
+\ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}A{\isacharunderscore}def\ simp\ del{\isacharcolon}L{\isacharunderscore}rhs{\isachardot}simps{\isacharparenright}\isanewline
+\ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{moreover}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}L\ {\isacharparenleft}arden{\isacharunderscore}variate\ X\ rhs{\isacharparenright}\ {\isacharequal}\ {\isacharparenleft}B\ {\isacharsemicolon}{\isacharsemicolon}\ A{\isasymstar}{\isacharparenright}{\isachardoublequoteclose}\ {\isacharparenleft}\isakeyword{is}\ {\isachardoublequoteopen}{\isacharquery}L\ {\isacharequal}\ {\isacharquery}R{\isachardoublequoteclose}{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}simp\ only{\isacharcolon}arden{\isacharunderscore}variate{\isacharunderscore}def\ L{\isacharunderscore}rhs{\isacharunderscore}union{\isacharunderscore}distrib\ lang{\isacharunderscore}of{\isacharunderscore}append{\isacharunderscore}rhs\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ B{\isacharunderscore}def\ A{\isacharunderscore}def\ b{\isacharunderscore}def\ L{\isacharunderscore}rexp{\isachardot}simps\ seq{\isacharunderscore}union{\isacharunderscore}distrib{\isacharparenright}\isanewline
+\ \ \ \isacommand{ultimately}\isamarkupfalse%
+\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ simp\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\ \isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ append{\isacharunderscore}keeps{\isacharunderscore}finite{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}finite\ rhs\ {\isasymLongrightarrow}\ finite\ {\isacharparenleft}append{\isacharunderscore}rhs{\isacharunderscore}rexp\ rhs\ r{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}append{\isacharunderscore}rhs{\isacharunderscore}rexp{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ arden{\isacharunderscore}variate{\isacharunderscore}keeps{\isacharunderscore}finite{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}finite\ rhs\ {\isasymLongrightarrow}\ finite\ {\isacharparenleft}arden{\isacharunderscore}variate\ X\ rhs{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}arden{\isacharunderscore}variate{\isacharunderscore}def\ append{\isacharunderscore}keeps{\isacharunderscore}finite{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ append{\isacharunderscore}keeps{\isacharunderscore}nonempty{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}rhs{\isacharunderscore}nonempty\ rhs\ {\isasymLongrightarrow}\ rhs{\isacharunderscore}nonempty\ {\isacharparenleft}append{\isacharunderscore}rhs{\isacharunderscore}rexp\ rhs\ r{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}rhs{\isacharunderscore}nonempty{\isacharunderscore}def\ append{\isacharunderscore}rhs{\isacharunderscore}rexp{\isacharunderscore}def{\isacharparenright}\isanewline
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}case{\isacharunderscore}tac\ x{\isacharcomma}\ auto\ simp{\isacharcolon}Seq{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ nonempty{\isacharunderscore}set{\isacharunderscore}sub{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}rhs{\isacharunderscore}nonempty\ rhs\ {\isasymLongrightarrow}\ rhs{\isacharunderscore}nonempty\ {\isacharparenleft}rhs\ {\isacharminus}\ A{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}rhs{\isacharunderscore}nonempty{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ nonempty{\isacharunderscore}set{\isacharunderscore}union{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}{\isasymlbrakk}rhs{\isacharunderscore}nonempty\ rhs{\isacharsemicolon}\ rhs{\isacharunderscore}nonempty\ rhs{\isacharprime}{\isasymrbrakk}\ {\isasymLongrightarrow}\ rhs{\isacharunderscore}nonempty\ {\isacharparenleft}rhs\ {\isasymunion}\ rhs{\isacharprime}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}rhs{\isacharunderscore}nonempty{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ arden{\isacharunderscore}variate{\isacharunderscore}keeps{\isacharunderscore}nonempty{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}rhs{\isacharunderscore}nonempty\ rhs\ {\isasymLongrightarrow}\ rhs{\isacharunderscore}nonempty\ {\isacharparenleft}arden{\isacharunderscore}variate\ X\ rhs{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}simp\ only{\isacharcolon}arden{\isacharunderscore}variate{\isacharunderscore}def\ append{\isacharunderscore}keeps{\isacharunderscore}nonempty\ nonempty{\isacharunderscore}set{\isacharunderscore}sub{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ rhs{\isacharunderscore}subst{\isacharunderscore}keeps{\isacharunderscore}nonempty{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}{\isasymlbrakk}rhs{\isacharunderscore}nonempty\ rhs{\isacharsemicolon}\ rhs{\isacharunderscore}nonempty\ xrhs{\isasymrbrakk}\ {\isasymLongrightarrow}\ rhs{\isacharunderscore}nonempty\ {\isacharparenleft}rhs{\isacharunderscore}subst\ rhs\ X\ xrhs{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}simp\ only{\isacharcolon}rhs{\isacharunderscore}subst{\isacharunderscore}def\ append{\isacharunderscore}keeps{\isacharunderscore}nonempty\ \ nonempty{\isacharunderscore}set{\isacharunderscore}union\ nonempty{\isacharunderscore}set{\isacharunderscore}sub{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ rhs{\isacharunderscore}subst{\isacharunderscore}keeps{\isacharunderscore}eq{\isacharcolon}\isanewline
+\ \ \isakeyword{assumes}\ substor{\isacharcolon}\ {\isachardoublequoteopen}X\ {\isacharequal}\ L\ xrhs{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{and}\ finite{\isacharcolon}\ {\isachardoublequoteopen}finite\ rhs{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{shows}\ {\isachardoublequoteopen}L\ {\isacharparenleft}rhs{\isacharunderscore}subst\ rhs\ X\ xrhs{\isacharparenright}\ {\isacharequal}\ L\ rhs{\isachardoublequoteclose}\ {\isacharparenleft}\isakeyword{is}\ {\isachardoublequoteopen}{\isacharquery}Left\ {\isacharequal}\ {\isacharquery}Right{\isachardoublequoteclose}{\isacharparenright}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+{\isacharminus}\isanewline
+\ \ \isacommand{def}\isamarkupfalse%
+\ A\ {\isasymequiv}\ {\isachardoublequoteopen}L\ {\isacharparenleft}rhs\ {\isacharminus}\ items{\isacharunderscore}of\ rhs\ X{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isacharquery}Left\ {\isacharequal}\ A\ {\isasymunion}\ L\ {\isacharparenleft}append{\isacharunderscore}rhs{\isacharunderscore}rexp\ xrhs\ {\isacharparenleft}rexp{\isacharunderscore}of\ rhs\ X{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}simp\ only{\isacharcolon}rhs{\isacharunderscore}subst{\isacharunderscore}def\ L{\isacharunderscore}rhs{\isacharunderscore}union{\isacharunderscore}distrib\ A{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \isacommand{moreover}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isacharquery}Right\ {\isacharequal}\ A\ {\isasymunion}\ L\ {\isacharparenleft}items{\isacharunderscore}of\ rhs\ X{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \isacommand{proof}\isamarkupfalse%
+{\isacharminus}\isanewline
+\ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}rhs\ {\isacharequal}\ {\isacharparenleft}rhs\ {\isacharminus}\ items{\isacharunderscore}of\ rhs\ X{\isacharparenright}\ {\isasymunion}\ {\isacharparenleft}items{\isacharunderscore}of\ rhs\ X{\isacharparenright}{\isachardoublequoteclose}\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}items{\isacharunderscore}of{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{thus}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}simp\ only{\isacharcolon}L{\isacharunderscore}rhs{\isacharunderscore}union{\isacharunderscore}distrib\ A{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{moreover}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}L\ {\isacharparenleft}append{\isacharunderscore}rhs{\isacharunderscore}rexp\ xrhs\ {\isacharparenleft}rexp{\isacharunderscore}of\ rhs\ X{\isacharparenright}{\isacharparenright}\ {\isacharequal}\ L\ {\isacharparenleft}items{\isacharunderscore}of\ rhs\ X{\isacharparenright}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \isacommand{using}\isamarkupfalse%
+\ finite\ substor\ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}simp\ only{\isacharcolon}lang{\isacharunderscore}of{\isacharunderscore}append{\isacharunderscore}rhs\ lang{\isacharunderscore}of{\isacharunderscore}rexp{\isacharunderscore}of{\isacharparenright}\isanewline
+\ \ \isacommand{ultimately}\isamarkupfalse%
+\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ simp\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ rhs{\isacharunderscore}subst{\isacharunderscore}keeps{\isacharunderscore}finite{\isacharunderscore}rhs{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}{\isasymlbrakk}finite\ rhs{\isacharsemicolon}\ finite\ yrhs{\isasymrbrakk}\ {\isasymLongrightarrow}\ finite\ {\isacharparenleft}rhs{\isacharunderscore}subst\ rhs\ Y\ yrhs{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}rhs{\isacharunderscore}subst{\isacharunderscore}def\ append{\isacharunderscore}keeps{\isacharunderscore}finite{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ eqs{\isacharunderscore}subst{\isacharunderscore}keeps{\isacharunderscore}finite{\isacharcolon}\isanewline
+\ \ \isakeyword{assumes}\ finite{\isacharcolon}{\isachardoublequoteopen}finite\ {\isacharparenleft}ES{\isacharcolon}{\isacharcolon}\ {\isacharparenleft}string\ set\ {\isasymtimes}\ rhs{\isacharunderscore}item\ set{\isacharparenright}\ set{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{shows}\ {\isachardoublequoteopen}finite\ {\isacharparenleft}eqs{\isacharunderscore}subst\ ES\ Y\ yrhs{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+\ {\isacharminus}\isanewline
+\ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}finite\ {\isacharbraceleft}{\isacharparenleft}Ya{\isacharcomma}\ rhs{\isacharunderscore}subst\ yrhsa\ Y\ yrhs{\isacharparenright}\ {\isacharbar}Ya\ yrhsa{\isachardot}\ {\isacharparenleft}Ya{\isacharcomma}\ yrhsa{\isacharparenright}\ {\isasymin}\ ES{\isacharbraceright}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ {\isacharparenleft}\isakeyword{is}\ {\isachardoublequoteopen}finite\ {\isacharquery}A{\isachardoublequoteclose}{\isacharparenright}\isanewline
+\ \ \isacommand{proof}\isamarkupfalse%
+{\isacharminus}\isanewline
+\ \ \ \ \isacommand{def}\isamarkupfalse%
+\ eqns{\isacharprime}\ {\isasymequiv}\ {\isachardoublequoteopen}{\isacharbraceleft}{\isacharparenleft}{\isacharparenleft}Ya{\isacharcolon}{\isacharcolon}string\ set{\isacharparenright}{\isacharcomma}\ yrhsa{\isacharparenright}{\isacharbar}\ Ya\ yrhsa{\isachardot}\ {\isacharparenleft}Ya{\isacharcomma}\ yrhsa{\isacharparenright}\ {\isasymin}\ ES{\isacharbraceright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{def}\isamarkupfalse%
+\ h\ {\isasymequiv}\ {\isachardoublequoteopen}{\isasymlambda}\ {\isacharparenleft}{\isacharparenleft}Ya{\isacharcolon}{\isacharcolon}string\ set{\isacharparenright}{\isacharcomma}\ yrhsa{\isacharparenright}{\isachardot}\ {\isacharparenleft}Ya{\isacharcomma}\ rhs{\isacharunderscore}subst\ yrhsa\ Y\ yrhs{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}finite\ {\isacharparenleft}h\ {\isacharbackquote}\ eqns{\isacharprime}{\isacharparenright}{\isachardoublequoteclose}\ \isacommand{using}\isamarkupfalse%
+\ finite\ h{\isacharunderscore}def\ eqns{\isacharprime}{\isacharunderscore}def\ \isacommand{by}\isamarkupfalse%
+\ auto\isanewline
+\ \ \ \ \isacommand{moreover}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isacharquery}A\ {\isacharequal}\ h\ {\isacharbackquote}\ eqns{\isacharprime}{\isachardoublequoteclose}\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}h{\isacharunderscore}def\ eqns{\isacharprime}{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{ultimately}\isamarkupfalse%
+\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ auto\ \ \ \ \ \ \isanewline
+\ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{thus}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}simp\ add{\isacharcolon}eqs{\isacharunderscore}subst{\isacharunderscore}def{\isacharparenright}\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ eqs{\isacharunderscore}subst{\isacharunderscore}keeps{\isacharunderscore}finite{\isacharunderscore}rhs{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}{\isasymlbrakk}finite{\isacharunderscore}rhs\ ES{\isacharsemicolon}\ finite\ yrhs{\isasymrbrakk}\ {\isasymLongrightarrow}\ finite{\isacharunderscore}rhs\ {\isacharparenleft}eqs{\isacharunderscore}subst\ ES\ Y\ yrhs{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ intro{\isacharcolon}rhs{\isacharunderscore}subst{\isacharunderscore}keeps{\isacharunderscore}finite{\isacharunderscore}rhs\ simp\ add{\isacharcolon}eqs{\isacharunderscore}subst{\isacharunderscore}def\ finite{\isacharunderscore}rhs{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ append{\isacharunderscore}rhs{\isacharunderscore}keeps{\isacharunderscore}cls{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}classes{\isacharunderscore}of\ {\isacharparenleft}append{\isacharunderscore}rhs{\isacharunderscore}rexp\ rhs\ r{\isacharparenright}\ {\isacharequal}\ classes{\isacharunderscore}of\ rhs{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}classes{\isacharunderscore}of{\isacharunderscore}def\ append{\isacharunderscore}rhs{\isacharunderscore}rexp{\isacharunderscore}def{\isacharparenright}\isanewline
+\isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}case{\isacharunderscore}tac\ xa{\isacharcomma}\ auto\ simp{\isacharcolon}image{\isacharunderscore}def{\isacharparenright}\isanewline
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}rule{\isacharunderscore}tac\ x\ {\isacharequal}\ {\isachardoublequoteopen}SEQ\ ra\ r{\isachardoublequoteclose}\ \isakeyword{in}\ exI{\isacharcomma}\ rule{\isacharunderscore}tac\ x\ {\isacharequal}\ {\isachardoublequoteopen}Trn\ x\ ra{\isachardoublequoteclose}\ \isakeyword{in}\ bexI{\isacharcomma}\ simp{\isacharplus}{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ arden{\isacharunderscore}variate{\isacharunderscore}removes{\isacharunderscore}cl{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}classes{\isacharunderscore}of\ {\isacharparenleft}arden{\isacharunderscore}variate\ Y\ yrhs{\isacharparenright}\ {\isacharequal}\ classes{\isacharunderscore}of\ yrhs\ {\isacharminus}\ {\isacharbraceleft}Y{\isacharbraceright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}simp\ add{\isacharcolon}arden{\isacharunderscore}variate{\isacharunderscore}def\ append{\isacharunderscore}rhs{\isacharunderscore}keeps{\isacharunderscore}cls\ items{\isacharunderscore}of{\isacharunderscore}def{\isacharparenright}\isanewline
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}classes{\isacharunderscore}of{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ lefts{\isacharunderscore}of{\isacharunderscore}keeps{\isacharunderscore}cls{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}lefts{\isacharunderscore}of\ {\isacharparenleft}eqs{\isacharunderscore}subst\ ES\ Y\ yrhs{\isacharparenright}\ {\isacharequal}\ lefts{\isacharunderscore}of\ ES{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}lefts{\isacharunderscore}of{\isacharunderscore}def\ eqs{\isacharunderscore}subst{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ rhs{\isacharunderscore}subst{\isacharunderscore}updates{\isacharunderscore}cls{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}X\ {\isasymnotin}\ classes{\isacharunderscore}of\ xrhs\ {\isasymLongrightarrow}\ \isanewline
+\ \ \ \ \ \ classes{\isacharunderscore}of\ {\isacharparenleft}rhs{\isacharunderscore}subst\ rhs\ X\ xrhs{\isacharparenright}\ {\isacharequal}\ classes{\isacharunderscore}of\ rhs\ {\isasymunion}\ classes{\isacharunderscore}of\ xrhs\ {\isacharminus}\ {\isacharbraceleft}X{\isacharbraceright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}simp\ only{\isacharcolon}rhs{\isacharunderscore}subst{\isacharunderscore}def\ append{\isacharunderscore}rhs{\isacharunderscore}keeps{\isacharunderscore}cls\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ classes{\isacharunderscore}of{\isacharunderscore}union{\isacharunderscore}distrib{\isacharbrackleft}THEN\ sym{\isacharbrackright}{\isacharparenright}\isanewline
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}classes{\isacharunderscore}of{\isacharunderscore}def\ items{\isacharunderscore}of{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ eqs{\isacharunderscore}subst{\isacharunderscore}keeps{\isacharunderscore}self{\isacharunderscore}contained{\isacharcolon}\isanewline
+\ \ \isakeyword{fixes}\ Y\isanewline
+\ \ \isakeyword{assumes}\ sc{\isacharcolon}\ {\isachardoublequoteopen}self{\isacharunderscore}contained\ {\isacharparenleft}ES\ {\isasymunion}\ {\isacharbraceleft}{\isacharparenleft}Y{\isacharcomma}\ yrhs{\isacharparenright}{\isacharbraceright}{\isacharparenright}{\isachardoublequoteclose}\ {\isacharparenleft}\isakeyword{is}\ {\isachardoublequoteopen}self{\isacharunderscore}contained\ {\isacharquery}A{\isachardoublequoteclose}{\isacharparenright}\isanewline
+\ \ \isakeyword{shows}\ {\isachardoublequoteopen}self{\isacharunderscore}contained\ {\isacharparenleft}eqs{\isacharunderscore}subst\ ES\ Y\ {\isacharparenleft}arden{\isacharunderscore}variate\ Y\ yrhs{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ {\isacharparenleft}\isakeyword{is}\ {\isachardoublequoteopen}self{\isacharunderscore}contained\ {\isacharquery}B{\isachardoublequoteclose}{\isacharparenright}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+{\isacharminus}\isanewline
+\ \ \isacommand{{\isacharbraceleft}}\isamarkupfalse%
+\ \isacommand{fix}\isamarkupfalse%
+\ X\ xrhs{\isacharprime}\isanewline
+\ \ \ \ \isacommand{assume}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isacharparenleft}X{\isacharcomma}\ xrhs{\isacharprime}{\isacharparenright}\ {\isasymin}\ {\isacharquery}B{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{then}\isamarkupfalse%
+\ \isacommand{obtain}\isamarkupfalse%
+\ xrhs\ \isanewline
+\ \ \ \ \ \ \isakeyword{where}\ xrhs{\isacharunderscore}xrhs{\isacharprime}{\isacharcolon}\ {\isachardoublequoteopen}xrhs{\isacharprime}\ {\isacharequal}\ rhs{\isacharunderscore}subst\ xrhs\ Y\ {\isacharparenleft}arden{\isacharunderscore}variate\ Y\ yrhs{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \isakeyword{and}\ X{\isacharunderscore}in{\isacharcolon}\ {\isachardoublequoteopen}{\isacharparenleft}X{\isacharcomma}\ xrhs{\isacharparenright}\ {\isasymin}\ ES{\isachardoublequoteclose}\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}simp\ add{\isacharcolon}eqs{\isacharunderscore}subst{\isacharunderscore}def{\isacharcomma}\ blast{\isacharparenright}\ \ \ \ \isanewline
+\ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}classes{\isacharunderscore}of\ xrhs{\isacharprime}\ {\isasymsubseteq}\ lefts{\isacharunderscore}of\ {\isacharquery}B{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{proof}\isamarkupfalse%
+{\isacharminus}\isanewline
+\ \ \ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}lefts{\isacharunderscore}of\ {\isacharquery}B\ {\isacharequal}\ lefts{\isacharunderscore}of\ ES{\isachardoublequoteclose}\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp\ add{\isacharcolon}lefts{\isacharunderscore}of{\isacharunderscore}def\ eqs{\isacharunderscore}subst{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \ \ \ \ \isacommand{moreover}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}classes{\isacharunderscore}of\ xrhs{\isacharprime}\ {\isasymsubseteq}\ lefts{\isacharunderscore}of\ ES{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \isacommand{proof}\isamarkupfalse%
+{\isacharminus}\isanewline
+\ \ \ \ \ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}classes{\isacharunderscore}of\ xrhs{\isacharprime}\ {\isasymsubseteq}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ classes{\isacharunderscore}of\ xrhs\ {\isasymunion}\ classes{\isacharunderscore}of\ {\isacharparenleft}arden{\isacharunderscore}variate\ Y\ yrhs{\isacharparenright}\ {\isacharminus}\ {\isacharbraceleft}Y{\isacharbraceright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \ \ \isacommand{proof}\isamarkupfalse%
+{\isacharminus}\isanewline
+\ \ \ \ \ \ \ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}Y\ {\isasymnotin}\ classes{\isacharunderscore}of\ {\isacharparenleft}arden{\isacharunderscore}variate\ Y\ yrhs{\isacharparenright}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \isacommand{using}\isamarkupfalse%
+\ arden{\isacharunderscore}variate{\isacharunderscore}removes{\isacharunderscore}cl\ \isacommand{by}\isamarkupfalse%
+\ simp\isanewline
+\ \ \ \ \ \ \ \ \ \ \isacommand{thus}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{using}\isamarkupfalse%
+\ xrhs{\isacharunderscore}xrhs{\isacharprime}\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}rhs{\isacharunderscore}subst{\isacharunderscore}updates{\isacharunderscore}cls{\isacharparenright}\isanewline
+\ \ \ \ \ \ \ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\ \ \ \ \ \ \ \ \isacommand{moreover}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}classes{\isacharunderscore}of\ xrhs\ {\isasymsubseteq}\ lefts{\isacharunderscore}of\ ES\ {\isasymunion}\ {\isacharbraceleft}Y{\isacharbraceright}{\isachardoublequoteclose}\ \isacommand{using}\isamarkupfalse%
+\ X{\isacharunderscore}in\ sc\isanewline
+\ \ \ \ \ \ \ \ \ \ \isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}simp\ only{\isacharcolon}self{\isacharunderscore}contained{\isacharunderscore}def\ lefts{\isacharunderscore}of{\isacharunderscore}union{\isacharunderscore}distrib{\isacharbrackleft}THEN\ sym{\isacharbrackright}{\isacharparenright}\isanewline
+\ \ \ \ \ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}drule{\isacharunderscore}tac\ x\ {\isacharequal}\ {\isachardoublequoteopen}{\isacharparenleft}X{\isacharcomma}\ xrhs{\isacharparenright}{\isachardoublequoteclose}\ \isakeyword{in}\ bspec{\isacharcomma}\ auto\ simp{\isacharcolon}lefts{\isacharunderscore}of{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \ \ \ \ \ \ \isacommand{moreover}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}classes{\isacharunderscore}of\ {\isacharparenleft}arden{\isacharunderscore}variate\ Y\ yrhs{\isacharparenright}\ {\isasymsubseteq}\ lefts{\isacharunderscore}of\ ES\ {\isasymunion}\ {\isacharbraceleft}Y{\isacharbraceright}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \isacommand{using}\isamarkupfalse%
+\ sc\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp\ add{\isacharcolon}arden{\isacharunderscore}variate{\isacharunderscore}removes{\isacharunderscore}cl\ self{\isacharunderscore}contained{\isacharunderscore}def\ lefts{\isacharunderscore}of{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \ \ \ \ \ \ \isacommand{ultimately}\isamarkupfalse%
+\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ auto\isanewline
+\ \ \ \ \ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\ \ \ \ \ \ \isacommand{ultimately}\isamarkupfalse%
+\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ simp\isanewline
+\ \ \ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{{\isacharbraceright}}\isamarkupfalse%
+\ \isacommand{thus}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp\ only{\isacharcolon}eqs{\isacharunderscore}subst{\isacharunderscore}def\ self{\isacharunderscore}contained{\isacharunderscore}def{\isacharparenright}\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ eqs{\isacharunderscore}subst{\isacharunderscore}satisfy{\isacharunderscore}Inv{\isacharcolon}\isanewline
+\ \ \isakeyword{assumes}\ Inv{\isacharunderscore}ES{\isacharcolon}\ {\isachardoublequoteopen}Inv\ {\isacharparenleft}ES\ {\isasymunion}\ {\isacharbraceleft}{\isacharparenleft}Y{\isacharcomma}\ yrhs{\isacharparenright}{\isacharbraceright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{shows}\ {\isachardoublequoteopen}Inv\ {\isacharparenleft}eqs{\isacharunderscore}subst\ ES\ Y\ {\isacharparenleft}arden{\isacharunderscore}variate\ Y\ yrhs{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+\ {\isacharminus}\ \ \isanewline
+\ \ \isacommand{have}\isamarkupfalse%
+\ finite{\isacharunderscore}yrhs{\isacharcolon}\ {\isachardoublequoteopen}finite\ yrhs{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \isacommand{using}\isamarkupfalse%
+\ Inv{\isacharunderscore}ES\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}Inv{\isacharunderscore}def\ finite{\isacharunderscore}rhs{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \isacommand{have}\isamarkupfalse%
+\ nonempty{\isacharunderscore}yrhs{\isacharcolon}\ {\isachardoublequoteopen}rhs{\isacharunderscore}nonempty\ yrhs{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \isacommand{using}\isamarkupfalse%
+\ Inv{\isacharunderscore}ES\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}Inv{\isacharunderscore}def\ ardenable{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \isacommand{have}\isamarkupfalse%
+\ Y{\isacharunderscore}eq{\isacharunderscore}yrhs{\isacharcolon}\ {\isachardoublequoteopen}Y\ {\isacharequal}\ L\ yrhs{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \isacommand{using}\isamarkupfalse%
+\ Inv{\isacharunderscore}ES\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}simp\ only{\isacharcolon}Inv{\isacharunderscore}def\ valid{\isacharunderscore}eqns{\isacharunderscore}def{\isacharcomma}\ blast{\isacharparenright}\isanewline
+\ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}distinct{\isacharunderscore}equas\ {\isacharparenleft}eqs{\isacharunderscore}subst\ ES\ Y\ {\isacharparenleft}arden{\isacharunderscore}variate\ Y\ yrhs{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \isacommand{using}\isamarkupfalse%
+\ Inv{\isacharunderscore}ES\isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}distinct{\isacharunderscore}equas{\isacharunderscore}def\ eqs{\isacharunderscore}subst{\isacharunderscore}def\ Inv{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \isacommand{moreover}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}finite\ {\isacharparenleft}eqs{\isacharunderscore}subst\ ES\ Y\ {\isacharparenleft}arden{\isacharunderscore}variate\ Y\ yrhs{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \isacommand{using}\isamarkupfalse%
+\ Inv{\isacharunderscore}ES\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}simp\ add{\isacharcolon}Inv{\isacharunderscore}def\ eqs{\isacharunderscore}subst{\isacharunderscore}keeps{\isacharunderscore}finite{\isacharparenright}\isanewline
+\ \ \isacommand{moreover}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}finite{\isacharunderscore}rhs\ {\isacharparenleft}eqs{\isacharunderscore}subst\ ES\ Y\ {\isacharparenleft}arden{\isacharunderscore}variate\ Y\ yrhs{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \isacommand{proof}\isamarkupfalse%
+{\isacharminus}\isanewline
+\ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}finite{\isacharunderscore}rhs\ ES{\isachardoublequoteclose}\ \isacommand{using}\isamarkupfalse%
+\ Inv{\isacharunderscore}ES\ \isanewline
+\ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}simp\ add{\isacharcolon}Inv{\isacharunderscore}def\ finite{\isacharunderscore}rhs{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{moreover}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}finite\ {\isacharparenleft}arden{\isacharunderscore}variate\ Y\ yrhs{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{proof}\isamarkupfalse%
+\ {\isacharminus}\isanewline
+\ \ \ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}finite\ yrhs{\isachardoublequoteclose}\ \isacommand{using}\isamarkupfalse%
+\ Inv{\isacharunderscore}ES\ \isanewline
+\ \ \ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}Inv{\isacharunderscore}def\ finite{\isacharunderscore}rhs{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \ \ \ \ \isacommand{thus}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{using}\isamarkupfalse%
+\ arden{\isacharunderscore}variate{\isacharunderscore}keeps{\isacharunderscore}finite\ \isacommand{by}\isamarkupfalse%
+\ simp\isanewline
+\ \ \ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\ \ \ \ \isacommand{ultimately}\isamarkupfalse%
+\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isanewline
+\ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}simp\ add{\isacharcolon}eqs{\isacharunderscore}subst{\isacharunderscore}keeps{\isacharunderscore}finite{\isacharunderscore}rhs{\isacharparenright}\isanewline
+\ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{moreover}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}ardenable\ {\isacharparenleft}eqs{\isacharunderscore}subst\ ES\ Y\ {\isacharparenleft}arden{\isacharunderscore}variate\ Y\ yrhs{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \isacommand{proof}\isamarkupfalse%
+\ {\isacharminus}\ \isanewline
+\ \ \ \ \isacommand{{\isacharbraceleft}}\isamarkupfalse%
+\ \isacommand{fix}\isamarkupfalse%
+\ X\ rhs\isanewline
+\ \ \ \ \ \ \isacommand{assume}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isacharparenleft}X{\isacharcomma}\ rhs{\isacharparenright}\ {\isasymin}\ ES{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \isacommand{hence}\isamarkupfalse%
+\ {\isachardoublequoteopen}rhs{\isacharunderscore}nonempty\ rhs{\isachardoublequoteclose}\ \ \isacommand{using}\isamarkupfalse%
+\ prems\ Inv{\isacharunderscore}ES\ \ \isanewline
+\ \ \ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}simp\ add{\isacharcolon}Inv{\isacharunderscore}def\ ardenable{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \ \ \ \ \isacommand{with}\isamarkupfalse%
+\ nonempty{\isacharunderscore}yrhs\ \isanewline
+\ \ \ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}rhs{\isacharunderscore}nonempty\ {\isacharparenleft}rhs{\isacharunderscore}subst\ rhs\ Y\ {\isacharparenleft}arden{\isacharunderscore}variate\ Y\ yrhs{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}simp\ add{\isacharcolon}nonempty{\isacharunderscore}yrhs\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ rhs{\isacharunderscore}subst{\isacharunderscore}keeps{\isacharunderscore}nonempty\ arden{\isacharunderscore}variate{\isacharunderscore}keeps{\isacharunderscore}nonempty{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{{\isacharbraceright}}\isamarkupfalse%
+\ \isacommand{thus}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp\ add{\isacharcolon}ardenable{\isacharunderscore}def\ eqs{\isacharunderscore}subst{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{moreover}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}valid{\isacharunderscore}eqns\ {\isacharparenleft}eqs{\isacharunderscore}subst\ ES\ Y\ {\isacharparenleft}arden{\isacharunderscore}variate\ Y\ yrhs{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \isacommand{proof}\isamarkupfalse%
+{\isacharminus}\isanewline
+\ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}Y\ {\isacharequal}\ L\ {\isacharparenleft}arden{\isacharunderscore}variate\ Y\ yrhs{\isacharparenright}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \ \ \isacommand{using}\isamarkupfalse%
+\ Y{\isacharunderscore}eq{\isacharunderscore}yrhs\ Inv{\isacharunderscore}ES\ finite{\isacharunderscore}yrhs\ nonempty{\isacharunderscore}yrhs\ \ \ \ \ \ \isanewline
+\ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}rule{\isacharunderscore}tac\ arden{\isacharunderscore}variate{\isacharunderscore}keeps{\isacharunderscore}eq{\isacharcomma}\ {\isacharparenleft}simp\ add{\isacharcolon}rexp{\isacharunderscore}of{\isacharunderscore}empty{\isacharparenright}{\isacharplus}{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{thus}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{using}\isamarkupfalse%
+\ Inv{\isacharunderscore}ES\ \isanewline
+\ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}clarsimp\ simp\ add{\isacharcolon}valid{\isacharunderscore}eqns{\isacharunderscore}def\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ eqs{\isacharunderscore}subst{\isacharunderscore}def\ rhs{\isacharunderscore}subst{\isacharunderscore}keeps{\isacharunderscore}eq\ Inv{\isacharunderscore}def\ finite{\isacharunderscore}rhs{\isacharunderscore}def\isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ simp\ del{\isacharcolon}L{\isacharunderscore}rhs{\isachardot}simps{\isacharparenright}\isanewline
+\ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{moreover}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ \isanewline
+\ \ \ \ non{\isacharunderscore}empty{\isacharunderscore}subst{\isacharcolon}\ {\isachardoublequoteopen}non{\isacharunderscore}empty\ {\isacharparenleft}eqs{\isacharunderscore}subst\ ES\ Y\ {\isacharparenleft}arden{\isacharunderscore}variate\ Y\ yrhs{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{using}\isamarkupfalse%
+\ Inv{\isacharunderscore}ES\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}Inv{\isacharunderscore}def\ non{\isacharunderscore}empty{\isacharunderscore}def\ eqs{\isacharunderscore}subst{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \isacommand{moreover}\isamarkupfalse%
+\ \isanewline
+\ \ \isacommand{have}\isamarkupfalse%
+\ self{\isacharunderscore}subst{\isacharcolon}\ {\isachardoublequoteopen}self{\isacharunderscore}contained\ {\isacharparenleft}eqs{\isacharunderscore}subst\ ES\ Y\ {\isacharparenleft}arden{\isacharunderscore}variate\ Y\ yrhs{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{using}\isamarkupfalse%
+\ Inv{\isacharunderscore}ES\ eqs{\isacharunderscore}subst{\isacharunderscore}keeps{\isacharunderscore}self{\isacharunderscore}contained\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}simp\ add{\isacharcolon}Inv{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \isacommand{ultimately}\isamarkupfalse%
+\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{using}\isamarkupfalse%
+\ Inv{\isacharunderscore}ES\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}simp\ add{\isacharcolon}Inv{\isacharunderscore}def{\isacharparenright}\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ eqs{\isacharunderscore}subst{\isacharunderscore}card{\isacharunderscore}le{\isacharcolon}\ \isanewline
+\ \ \isakeyword{assumes}\ finite{\isacharcolon}\ {\isachardoublequoteopen}finite\ {\isacharparenleft}ES{\isacharcolon}{\isacharcolon}{\isacharparenleft}string\ set\ {\isasymtimes}\ rhs{\isacharunderscore}item\ set{\isacharparenright}\ set{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{shows}\ {\isachardoublequoteopen}card\ {\isacharparenleft}eqs{\isacharunderscore}subst\ ES\ Y\ yrhs{\isacharparenright}\ {\isacharless}{\isacharequal}\ card\ ES{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+{\isacharminus}\isanewline
+\ \ \isacommand{def}\isamarkupfalse%
+\ f\ {\isasymequiv}\ {\isachardoublequoteopen}{\isasymlambda}\ x{\isachardot}\ {\isacharparenleft}{\isacharparenleft}fst\ x{\isacharparenright}{\isacharcolon}{\isacharcolon}string\ set{\isacharcomma}\ rhs{\isacharunderscore}subst\ {\isacharparenleft}snd\ x{\isacharparenright}\ Y\ yrhs{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}eqs{\isacharunderscore}subst\ ES\ Y\ yrhs\ {\isacharequal}\ f\ {\isacharbackquote}\ ES{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}eqs{\isacharunderscore}subst{\isacharunderscore}def\ f{\isacharunderscore}def\ image{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}rule{\isacharunderscore}tac\ x\ {\isacharequal}\ {\isachardoublequoteopen}{\isacharparenleft}Ya{\isacharcomma}\ yrhsa{\isacharparenright}{\isachardoublequoteclose}\ \isakeyword{in}\ bexI{\isacharcomma}\ simp{\isacharplus}{\isacharparenright}\isanewline
+\ \ \isacommand{thus}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{using}\isamarkupfalse%
+\ finite\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ intro{\isacharcolon}card{\isacharunderscore}image{\isacharunderscore}le{\isacharparenright}\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ eqs{\isacharunderscore}subst{\isacharunderscore}cls{\isacharunderscore}remains{\isacharcolon}\ \isanewline
+\ \ {\isachardoublequoteopen}{\isacharparenleft}X{\isacharcomma}\ xrhs{\isacharparenright}\ {\isasymin}\ ES\ {\isasymLongrightarrow}\ {\isasymexists}\ xrhs{\isacharprime}{\isachardot}\ {\isacharparenleft}X{\isacharcomma}\ xrhs{\isacharprime}{\isacharparenright}\ {\isasymin}\ {\isacharparenleft}eqs{\isacharunderscore}subst\ ES\ Y\ yrhs{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}eqs{\isacharunderscore}subst{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ card{\isacharunderscore}noteq{\isacharunderscore}{\isadigit{1}}{\isacharunderscore}has{\isacharunderscore}more{\isacharcolon}\isanewline
+\ \ \isakeyword{assumes}\ card{\isacharcolon}{\isachardoublequoteopen}card\ S\ {\isasymnoteq}\ {\isadigit{1}}{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{and}\ e{\isacharunderscore}in{\isacharcolon}\ {\isachardoublequoteopen}e\ {\isasymin}\ S{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{and}\ finite{\isacharcolon}\ {\isachardoublequoteopen}finite\ S{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{obtains}\ e{\isacharprime}\ \isakeyword{where}\ {\isachardoublequoteopen}e{\isacharprime}\ {\isasymin}\ S\ {\isasymand}\ e\ {\isasymnoteq}\ e{\isacharprime}{\isachardoublequoteclose}\ \isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+{\isacharminus}\isanewline
+\ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}card\ {\isacharparenleft}S\ {\isacharminus}\ {\isacharbraceleft}e{\isacharbraceright}{\isacharparenright}\ {\isachargreater}\ {\isadigit{0}}{\isachardoublequoteclose}\isanewline
+\ \ \isacommand{proof}\isamarkupfalse%
+\ {\isacharminus}\isanewline
+\ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}card\ S\ {\isachargreater}\ {\isadigit{1}}{\isachardoublequoteclose}\ \isacommand{using}\isamarkupfalse%
+\ card\ e{\isacharunderscore}in\ finite\ \ \isanewline
+\ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}case{\isacharunderscore}tac\ {\isachardoublequoteopen}card\ S{\isachardoublequoteclose}{\isacharcomma}\ auto{\isacharparenright}\ \isanewline
+\ \ \ \ \isacommand{thus}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{using}\isamarkupfalse%
+\ finite\ e{\isacharunderscore}in\ \isacommand{by}\isamarkupfalse%
+\ auto\isanewline
+\ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{hence}\isamarkupfalse%
+\ {\isachardoublequoteopen}S\ {\isacharminus}\ {\isacharbraceleft}e{\isacharbraceright}\ {\isasymnoteq}\ {\isacharbraceleft}{\isacharbraceright}{\isachardoublequoteclose}\ \isacommand{using}\isamarkupfalse%
+\ finite\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}rule{\isacharunderscore}tac\ notI{\isacharcomma}\ simp{\isacharparenright}\isanewline
+\ \ \isacommand{thus}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isacharparenleft}{\isasymAnd}e{\isacharprime}{\isachardot}\ e{\isacharprime}\ {\isasymin}\ S\ {\isasymand}\ e\ {\isasymnoteq}\ e{\isacharprime}\ {\isasymLongrightarrow}\ thesis{\isacharparenright}\ {\isasymLongrightarrow}\ thesis{\isachardoublequoteclose}\ \isacommand{by}\isamarkupfalse%
+\ auto\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ iteration{\isacharunderscore}step{\isacharcolon}\ \isanewline
+\ \ \isakeyword{assumes}\ Inv{\isacharunderscore}ES{\isacharcolon}\ {\isachardoublequoteopen}Inv\ ES{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{and}\ \ \ \ X{\isacharunderscore}in{\isacharunderscore}ES{\isacharcolon}\ {\isachardoublequoteopen}{\isacharparenleft}X{\isacharcomma}\ xrhs{\isacharparenright}\ {\isasymin}\ ES{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{and}\ \ \ \ not{\isacharunderscore}T{\isacharcolon}\ {\isachardoublequoteopen}card\ ES\ {\isasymnoteq}\ {\isadigit{1}}{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{shows}\ {\isachardoublequoteopen}{\isasymexists}\ ES{\isacharprime}{\isachardot}\ {\isacharparenleft}Inv\ ES{\isacharprime}\ {\isasymand}\ {\isacharparenleft}{\isasymexists}\ xrhs{\isacharprime}{\isachardot}{\isacharparenleft}X{\isacharcomma}\ xrhs{\isacharprime}{\isacharparenright}\ {\isasymin}\ ES{\isacharprime}{\isacharparenright}{\isacharparenright}\ {\isasymand}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ {\isacharparenleft}card\ ES{\isacharprime}{\isacharcomma}\ card\ ES{\isacharparenright}\ {\isasymin}\ less{\isacharunderscore}than{\isachardoublequoteclose}\ {\isacharparenleft}\isakeyword{is}\ {\isachardoublequoteopen}{\isasymexists}\ ES{\isacharprime}{\isachardot}\ {\isacharquery}P\ ES{\isacharprime}{\isachardoublequoteclose}{\isacharparenright}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+\ {\isacharminus}\isanewline
+\ \ \isacommand{have}\isamarkupfalse%
+\ finite{\isacharunderscore}ES{\isacharcolon}\ {\isachardoublequoteopen}finite\ ES{\isachardoublequoteclose}\ \isacommand{using}\isamarkupfalse%
+\ Inv{\isacharunderscore}ES\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}simp\ add{\isacharcolon}Inv{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \isacommand{then}\isamarkupfalse%
+\ \isacommand{obtain}\isamarkupfalse%
+\ Y\ yrhs\ \isanewline
+\ \ \ \ \isakeyword{where}\ Y{\isacharunderscore}in{\isacharunderscore}ES{\isacharcolon}\ {\isachardoublequoteopen}{\isacharparenleft}Y{\isacharcomma}\ yrhs{\isacharparenright}\ {\isasymin}\ ES{\isachardoublequoteclose}\ \isakeyword{and}\ not{\isacharunderscore}eq{\isacharcolon}\ {\isachardoublequoteopen}{\isacharparenleft}X{\isacharcomma}\ xrhs{\isacharparenright}\ {\isasymnoteq}\ {\isacharparenleft}Y{\isacharcomma}\ yrhs{\isacharparenright}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \isacommand{using}\isamarkupfalse%
+\ not{\isacharunderscore}T\ X{\isacharunderscore}in{\isacharunderscore}ES\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}drule{\isacharunderscore}tac\ card{\isacharunderscore}noteq{\isacharunderscore}{\isadigit{1}}{\isacharunderscore}has{\isacharunderscore}more{\isacharcomma}\ auto{\isacharparenright}\isanewline
+\ \ \isacommand{def}\isamarkupfalse%
+\ ES{\isacharprime}\ {\isacharequal}{\isacharequal}\ {\isachardoublequoteopen}ES\ {\isacharminus}\ {\isacharbraceleft}{\isacharparenleft}Y{\isacharcomma}\ yrhs{\isacharparenright}{\isacharbraceright}{\isachardoublequoteclose}\isanewline
+\ \ \isacommand{let}\isamarkupfalse%
+\ {\isacharquery}ES{\isacharprime}{\isacharprime}\ {\isacharequal}\ {\isachardoublequoteopen}eqs{\isacharunderscore}subst\ ES{\isacharprime}\ Y\ {\isacharparenleft}arden{\isacharunderscore}variate\ Y\ yrhs{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isacharquery}P\ {\isacharquery}ES{\isacharprime}{\isacharprime}{\isachardoublequoteclose}\isanewline
+\ \ \isacommand{proof}\isamarkupfalse%
+\ {\isacharminus}\isanewline
+\ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}Inv\ {\isacharquery}ES{\isacharprime}{\isacharprime}{\isachardoublequoteclose}\ \isacommand{using}\isamarkupfalse%
+\ Y{\isacharunderscore}in{\isacharunderscore}ES\ Inv{\isacharunderscore}ES\isanewline
+\ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}rule{\isacharunderscore}tac\ eqs{\isacharunderscore}subst{\isacharunderscore}satisfy{\isacharunderscore}Inv{\isacharcomma}\ simp\ add{\isacharcolon}ES{\isacharprime}{\isacharunderscore}def\ insert{\isacharunderscore}absorb{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{moreover}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isasymexists}xrhs{\isacharprime}{\isachardot}\ {\isacharparenleft}X{\isacharcomma}\ xrhs{\isacharprime}{\isacharparenright}\ {\isasymin}\ {\isacharquery}ES{\isacharprime}{\isacharprime}{\isachardoublequoteclose}\ \ \isacommand{using}\isamarkupfalse%
+\ not{\isacharunderscore}eq\ X{\isacharunderscore}in{\isacharunderscore}ES\isanewline
+\ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}rule{\isacharunderscore}tac\ ES\ {\isacharequal}\ ES{\isacharprime}\ \isakeyword{in}\ eqs{\isacharunderscore}subst{\isacharunderscore}cls{\isacharunderscore}remains{\isacharcomma}\ auto\ simp\ add{\isacharcolon}ES{\isacharprime}{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{moreover}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isacharparenleft}card\ {\isacharquery}ES{\isacharprime}{\isacharprime}{\isacharcomma}\ card\ ES{\isacharparenright}\ {\isasymin}\ less{\isacharunderscore}than{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \isacommand{proof}\isamarkupfalse%
+\ {\isacharminus}\isanewline
+\ \ \ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}finite\ ES{\isacharprime}{\isachardoublequoteclose}\ \isacommand{using}\isamarkupfalse%
+\ finite{\isacharunderscore}ES\ ES{\isacharprime}{\isacharunderscore}def\ \isacommand{by}\isamarkupfalse%
+\ auto\isanewline
+\ \ \ \ \ \ \isacommand{moreover}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}card\ ES{\isacharprime}\ {\isacharless}\ card\ ES{\isachardoublequoteclose}\ \isacommand{using}\isamarkupfalse%
+\ finite{\isacharunderscore}ES\ Y{\isacharunderscore}in{\isacharunderscore}ES\isanewline
+\ \ \ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}ES{\isacharprime}{\isacharunderscore}def\ card{\isacharunderscore}gt{\isacharunderscore}{\isadigit{0}}{\isacharunderscore}iff\ intro{\isacharcolon}diff{\isacharunderscore}Suc{\isacharunderscore}less{\isacharparenright}\isanewline
+\ \ \ \ \ \ \isacommand{ultimately}\isamarkupfalse%
+\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isanewline
+\ \ \ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ dest{\isacharcolon}eqs{\isacharunderscore}subst{\isacharunderscore}card{\isacharunderscore}le\ elim{\isacharcolon}le{\isacharunderscore}less{\isacharunderscore}trans{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\ \ \ \ \isacommand{ultimately}\isamarkupfalse%
+\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ simp\isanewline
+\ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{thus}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ blast\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\begin{isamarkuptext}%
+From this point until \isa{hard{\isacharunderscore}direction}, the hard direction is proved
+ through a simple application of the iteration principle.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{lemma}\isamarkupfalse%
+\ iteration{\isacharunderscore}conc{\isacharcolon}\ \isanewline
+\ \ \isakeyword{assumes}\ history{\isacharcolon}\ {\isachardoublequoteopen}Inv\ ES{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{and}\ \ \ \ X{\isacharunderscore}in{\isacharunderscore}ES{\isacharcolon}\ {\isachardoublequoteopen}{\isasymexists}\ xrhs{\isachardot}\ {\isacharparenleft}X{\isacharcomma}\ xrhs{\isacharparenright}\ {\isasymin}\ ES{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{shows}\ \isanewline
+\ \ {\isachardoublequoteopen}{\isasymexists}\ ES{\isacharprime}{\isachardot}\ {\isacharparenleft}Inv\ ES{\isacharprime}\ {\isasymand}\ {\isacharparenleft}{\isasymexists}\ xrhs{\isacharprime}{\isachardot}\ {\isacharparenleft}X{\isacharcomma}\ xrhs{\isacharprime}{\isacharparenright}\ {\isasymin}\ ES{\isacharprime}{\isacharparenright}{\isacharparenright}\ {\isasymand}\ card\ ES{\isacharprime}\ {\isacharequal}\ {\isadigit{1}}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ {\isacharparenleft}\isakeyword{is}\ {\isachardoublequoteopen}{\isasymexists}\ ES{\isacharprime}{\isachardot}\ {\isacharquery}P\ ES{\isacharprime}{\isachardoublequoteclose}{\isacharparenright}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+\ {\isacharparenleft}cases\ {\isachardoublequoteopen}card\ ES\ {\isacharequal}\ {\isadigit{1}}{\isachardoublequoteclose}{\isacharparenright}\isanewline
+\ \ \isacommand{case}\isamarkupfalse%
+\ True\isanewline
+\ \ \isacommand{thus}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{using}\isamarkupfalse%
+\ history\ X{\isacharunderscore}in{\isacharunderscore}ES\isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ blast\isanewline
+\isacommand{next}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{case}\isamarkupfalse%
+\ False\ \ \isanewline
+\ \ \isacommand{thus}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{using}\isamarkupfalse%
+\ history\ iteration{\isacharunderscore}step\ X{\isacharunderscore}in{\isacharunderscore}ES\isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}rule{\isacharunderscore}tac\ f\ {\isacharequal}\ card\ \isakeyword{in}\ wf{\isacharunderscore}iter{\isacharcomma}\ auto{\isacharparenright}\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\ \ \isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ last{\isacharunderscore}cl{\isacharunderscore}exists{\isacharunderscore}rexp{\isacharcolon}\isanewline
+\ \ \isakeyword{assumes}\ ES{\isacharunderscore}single{\isacharcolon}\ {\isachardoublequoteopen}ES\ {\isacharequal}\ {\isacharbraceleft}{\isacharparenleft}X{\isacharcomma}\ xrhs{\isacharparenright}{\isacharbraceright}{\isachardoublequoteclose}\ \isanewline
+\ \ \isakeyword{and}\ Inv{\isacharunderscore}ES{\isacharcolon}\ {\isachardoublequoteopen}Inv\ ES{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{shows}\ {\isachardoublequoteopen}{\isasymexists}\ {\isacharparenleft}r{\isacharcolon}{\isacharcolon}rexp{\isacharparenright}{\isachardot}\ L\ r\ {\isacharequal}\ X{\isachardoublequoteclose}\ {\isacharparenleft}\isakeyword{is}\ {\isachardoublequoteopen}{\isasymexists}\ r{\isachardot}\ {\isacharquery}P\ r{\isachardoublequoteclose}{\isacharparenright}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+{\isacharminus}\isanewline
+\ \ \isacommand{let}\isamarkupfalse%
+\ {\isacharquery}A\ {\isacharequal}\ {\isachardoublequoteopen}arden{\isacharunderscore}variate\ X\ xrhs{\isachardoublequoteclose}\isanewline
+\ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isacharquery}P\ {\isacharparenleft}rexp{\isacharunderscore}of{\isacharunderscore}lam\ {\isacharquery}A{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \isacommand{proof}\isamarkupfalse%
+\ {\isacharminus}\isanewline
+\ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}L\ {\isacharparenleft}rexp{\isacharunderscore}of{\isacharunderscore}lam\ {\isacharquery}A{\isacharparenright}\ {\isacharequal}\ L\ {\isacharparenleft}lam{\isacharunderscore}of\ {\isacharquery}A{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{proof}\isamarkupfalse%
+{\isacharparenleft}rule\ rexp{\isacharunderscore}of{\isacharunderscore}lam{\isacharunderscore}eq{\isacharunderscore}lam{\isacharunderscore}set{\isacharparenright}\isanewline
+\ \ \ \ \ \ \isacommand{show}\isamarkupfalse%
+\ {\isachardoublequoteopen}finite\ {\isacharparenleft}arden{\isacharunderscore}variate\ X\ xrhs{\isacharparenright}{\isachardoublequoteclose}\ \isacommand{using}\isamarkupfalse%
+\ Inv{\isacharunderscore}ES\ ES{\isacharunderscore}single\ \isanewline
+\ \ \ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}rule{\isacharunderscore}tac\ arden{\isacharunderscore}variate{\isacharunderscore}keeps{\isacharunderscore}finite{\isacharcomma}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ auto\ simp\ add{\isacharcolon}Inv{\isacharunderscore}def\ finite{\isacharunderscore}rhs{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\ \ \ \ \isacommand{also}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isasymdots}\ {\isacharequal}\ L\ {\isacharquery}A{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{proof}\isamarkupfalse%
+{\isacharminus}\isanewline
+\ \ \ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}lam{\isacharunderscore}of\ {\isacharquery}A\ {\isacharequal}\ {\isacharquery}A{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \isacommand{proof}\isamarkupfalse%
+{\isacharminus}\isanewline
+\ \ \ \ \ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}classes{\isacharunderscore}of\ {\isacharquery}A\ {\isacharequal}\ {\isacharbraceleft}{\isacharbraceright}{\isachardoublequoteclose}\ \isacommand{using}\isamarkupfalse%
+\ Inv{\isacharunderscore}ES\ ES{\isacharunderscore}single\isanewline
+\ \ \ \ \ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}simp\ add{\isacharcolon}arden{\isacharunderscore}variate{\isacharunderscore}removes{\isacharunderscore}cl\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ self{\isacharunderscore}contained{\isacharunderscore}def\ Inv{\isacharunderscore}def\ lefts{\isacharunderscore}of{\isacharunderscore}def{\isacharparenright}\ \isanewline
+\ \ \ \ \ \ \ \ \isacommand{thus}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp\ only{\isacharcolon}lam{\isacharunderscore}of{\isacharunderscore}def\ classes{\isacharunderscore}of{\isacharunderscore}def{\isacharcomma}\ case{\isacharunderscore}tac\ x{\isacharcomma}\ auto{\isacharparenright}\isanewline
+\ \ \ \ \ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\ \ \ \ \ \ \isacommand{thus}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ simp\isanewline
+\ \ \ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\ \ \ \ \isacommand{also}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isasymdots}\ {\isacharequal}\ X{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{proof}\isamarkupfalse%
+{\isacharparenleft}rule\ arden{\isacharunderscore}variate{\isacharunderscore}keeps{\isacharunderscore}eq\ {\isacharbrackleft}THEN\ sym{\isacharbrackright}{\isacharparenright}\isanewline
+\ \ \ \ \ \ \isacommand{show}\isamarkupfalse%
+\ {\isachardoublequoteopen}X\ {\isacharequal}\ L\ xrhs{\isachardoublequoteclose}\ \isacommand{using}\isamarkupfalse%
+\ Inv{\isacharunderscore}ES\ ES{\isacharunderscore}single\ \isanewline
+\ \ \ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp\ only{\isacharcolon}Inv{\isacharunderscore}def\ valid{\isacharunderscore}eqns{\isacharunderscore}def{\isacharparenright}\ \ \isanewline
+\ \ \ \ \isacommand{next}\isamarkupfalse%
+\isanewline
+\ \ \ \ \ \ \isacommand{from}\isamarkupfalse%
+\ Inv{\isacharunderscore}ES\ ES{\isacharunderscore}single\ \isacommand{show}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isacharbrackleft}{\isacharbrackright}\ {\isasymnotin}\ L\ {\isacharparenleft}rexp{\isacharunderscore}of\ xrhs\ X{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+{\isacharparenleft}simp\ add{\isacharcolon}Inv{\isacharunderscore}def\ ardenable{\isacharunderscore}def\ rexp{\isacharunderscore}of{\isacharunderscore}empty\ finite{\isacharunderscore}rhs{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{next}\isamarkupfalse%
+\isanewline
+\ \ \ \ \ \ \isacommand{from}\isamarkupfalse%
+\ Inv{\isacharunderscore}ES\ ES{\isacharunderscore}single\ \isacommand{show}\isamarkupfalse%
+\ {\isachardoublequoteopen}finite\ xrhs{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}simp\ add{\isacharcolon}Inv{\isacharunderscore}def\ finite{\isacharunderscore}rhs{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\ \ \ \ \isacommand{finally}\isamarkupfalse%
+\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ simp\isanewline
+\ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{thus}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ auto\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\ \ \ \isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ every{\isacharunderscore}eqcl{\isacharunderscore}has{\isacharunderscore}reg{\isacharcolon}\ \isanewline
+\ \ \isakeyword{assumes}\ finite{\isacharunderscore}CS{\isacharcolon}\ {\isachardoublequoteopen}finite\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isacharparenleft}{\isasymapprox}Lang{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{and}\ X{\isacharunderscore}in{\isacharunderscore}CS{\isacharcolon}\ {\isachardoublequoteopen}X\ {\isasymin}\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isacharparenleft}{\isasymapprox}Lang{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{shows}\ {\isachardoublequoteopen}{\isasymexists}\ {\isacharparenleft}reg{\isacharcolon}{\isacharcolon}rexp{\isacharparenright}{\isachardot}\ L\ reg\ {\isacharequal}\ X{\isachardoublequoteclose}\ {\isacharparenleft}\isakeyword{is}\ {\isachardoublequoteopen}{\isasymexists}\ r{\isachardot}\ {\isacharquery}E\ r{\isachardoublequoteclose}{\isacharparenright}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+\ {\isacharminus}\isanewline
+\ \ \isacommand{from}\isamarkupfalse%
+\ X{\isacharunderscore}in{\isacharunderscore}CS\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isasymexists}\ xrhs{\isachardot}\ {\isacharparenleft}X{\isacharcomma}\ xrhs{\isacharparenright}\ {\isasymin}\ {\isacharparenleft}eqs\ {\isacharparenleft}UNIV\ \ {\isacharslash}{\isacharslash}\ {\isacharparenleft}{\isasymapprox}Lang{\isacharparenright}{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}eqs{\isacharunderscore}def\ init{\isacharunderscore}rhs{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \isacommand{then}\isamarkupfalse%
+\ \isacommand{obtain}\isamarkupfalse%
+\ ES\ xrhs\ \isakeyword{where}\ Inv{\isacharunderscore}ES{\isacharcolon}\ {\isachardoublequoteopen}Inv\ ES{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \isakeyword{and}\ X{\isacharunderscore}in{\isacharunderscore}ES{\isacharcolon}\ {\isachardoublequoteopen}{\isacharparenleft}X{\isacharcomma}\ xrhs{\isacharparenright}\ {\isasymin}\ ES{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isakeyword{and}\ card{\isacharunderscore}ES{\isacharcolon}\ {\isachardoublequoteopen}card\ ES\ {\isacharequal}\ {\isadigit{1}}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{using}\isamarkupfalse%
+\ finite{\isacharunderscore}CS\ X{\isacharunderscore}in{\isacharunderscore}CS\ init{\isacharunderscore}ES{\isacharunderscore}satisfy{\isacharunderscore}Inv\ iteration{\isacharunderscore}conc\isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ blast\isanewline
+\ \ \isacommand{hence}\isamarkupfalse%
+\ ES{\isacharunderscore}single{\isacharunderscore}equa{\isacharcolon}\ {\isachardoublequoteopen}ES\ {\isacharequal}\ {\isacharbraceleft}{\isacharparenleft}X{\isacharcomma}\ xrhs{\isacharparenright}{\isacharbraceright}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}Inv{\isacharunderscore}def\ dest{\isacharbang}{\isacharcolon}card{\isacharunderscore}Suc{\isacharunderscore}Diff{\isadigit{1}}\ simp{\isacharcolon}card{\isacharunderscore}eq{\isacharunderscore}{\isadigit{0}}{\isacharunderscore}iff{\isacharparenright}\ \isanewline
+\ \ \isacommand{thus}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{using}\isamarkupfalse%
+\ Inv{\isacharunderscore}ES\isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}rule\ last{\isacharunderscore}cl{\isacharunderscore}exists{\isacharunderscore}rexp{\isacharparenright}\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ finals{\isacharunderscore}in{\isacharunderscore}partitions{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}finals\ Lang\ {\isasymsubseteq}\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isacharparenleft}{\isasymapprox}Lang{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+\ \ %
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}finals{\isacharunderscore}def\ quotient{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\ \ \ \isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{theorem}\isamarkupfalse%
+\ hard{\isacharunderscore}direction{\isacharcolon}\ \isanewline
+\ \ \isakeyword{assumes}\ finite{\isacharunderscore}CS{\isacharcolon}\ {\isachardoublequoteopen}finite\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isacharparenleft}{\isasymapprox}Lang{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{shows}\ \ \ {\isachardoublequoteopen}{\isasymexists}\ {\isacharparenleft}reg{\isacharcolon}{\isacharcolon}rexp{\isacharparenright}{\isachardot}\ Lang\ {\isacharequal}\ L\ reg{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+\ {\isacharminus}\isanewline
+\ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isasymforall}\ X\ {\isasymin}\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isacharparenleft}{\isasymapprox}Lang{\isacharparenright}{\isacharparenright}{\isachardot}\ {\isasymexists}\ {\isacharparenleft}reg{\isacharcolon}{\isacharcolon}rexp{\isacharparenright}{\isachardot}\ X\ {\isacharequal}\ L\ reg{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \isacommand{using}\isamarkupfalse%
+\ finite{\isacharunderscore}CS\ every{\isacharunderscore}eqcl{\isacharunderscore}has{\isacharunderscore}reg\ \isacommand{by}\isamarkupfalse%
+\ blast\isanewline
+\ \ \isacommand{then}\isamarkupfalse%
+\ \isacommand{obtain}\isamarkupfalse%
+\ f\ \isanewline
+\ \ \ \ \isakeyword{where}\ f{\isacharunderscore}prop{\isacharcolon}\ {\isachardoublequoteopen}{\isasymforall}\ X\ {\isasymin}\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isacharparenleft}{\isasymapprox}Lang{\isacharparenright}{\isacharparenright}{\isachardot}\ X\ {\isacharequal}\ L\ {\isacharparenleft}{\isacharparenleft}f\ X{\isacharparenright}{\isacharcolon}{\isacharcolon}rexp{\isacharparenright}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ dest{\isacharcolon}bchoice{\isacharparenright}\isanewline
+\ \ \isacommand{def}\isamarkupfalse%
+\ rs\ {\isasymequiv}\ {\isachardoublequoteopen}f\ {\isacharbackquote}\ {\isacharparenleft}finals\ Lang{\isacharparenright}{\isachardoublequoteclose}\ \ \isanewline
+\ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}Lang\ {\isacharequal}\ {\isasymUnion}\ {\isacharparenleft}finals\ Lang{\isacharparenright}{\isachardoublequoteclose}\ \isacommand{using}\isamarkupfalse%
+\ lang{\isacharunderscore}is{\isacharunderscore}union{\isacharunderscore}of{\isacharunderscore}finals\ \isacommand{by}\isamarkupfalse%
+\ auto\isanewline
+\ \ \isacommand{also}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isasymdots}\ {\isacharequal}\ L\ {\isacharparenleft}folds\ ALT\ NULL\ rs{\isacharparenright}{\isachardoublequoteclose}\ \isanewline
+\ \ \isacommand{proof}\isamarkupfalse%
+\ {\isacharminus}\isanewline
+\ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}finite\ rs{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{proof}\isamarkupfalse%
+\ {\isacharminus}\isanewline
+\ \ \ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}finite\ {\isacharparenleft}finals\ Lang{\isacharparenright}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \ \ \ \ \isacommand{using}\isamarkupfalse%
+\ finite{\isacharunderscore}CS\ finals{\isacharunderscore}in{\isacharunderscore}partitions{\isacharbrackleft}of\ {\isachardoublequoteopen}Lang{\isachardoublequoteclose}{\isacharbrackright}\ \ \ \isanewline
+\ \ \ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}erule{\isacharunderscore}tac\ finite{\isacharunderscore}subset{\isacharcomma}\ simp{\isacharparenright}\isanewline
+\ \ \ \ \ \ \isacommand{thus}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{using}\isamarkupfalse%
+\ rs{\isacharunderscore}def\ \isacommand{by}\isamarkupfalse%
+\ auto\isanewline
+\ \ \ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\ \ \ \ \isacommand{thus}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isanewline
+\ \ \ \ \ \ \isacommand{using}\isamarkupfalse%
+\ f{\isacharunderscore}prop\ rs{\isacharunderscore}def\ finals{\isacharunderscore}in{\isacharunderscore}partitions{\isacharbrackleft}of\ {\isachardoublequoteopen}Lang{\isachardoublequoteclose}{\isacharbrackright}\ \isacommand{by}\isamarkupfalse%
+\ auto\isanewline
+\ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{finally}\isamarkupfalse%
+\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ blast\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isamarkupsection{Direction: \isa{regular\ language\ {\isasymRightarrow}finite\ partition}%
+}
+\isamarkuptrue%
+%
+\isamarkupsubsection{The scheme for this direction%
+}
+\isamarkuptrue%
+%
+\begin{isamarkuptext}%
+The following convenient notation \isa{x\ {\isasymapprox}Lang\ y} means:
+ string \isa{x} and \isa{y} are equivalent with respect to
+ language \isa{Lang}.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{definition}\isamarkupfalse%
+\isanewline
+\ \ str{\isacharunderscore}eq\ {\isacharparenleft}{\isachardoublequoteopen}{\isacharunderscore}\ {\isasymapprox}{\isacharunderscore}\ {\isacharunderscore}{\isachardoublequoteclose}{\isacharparenright}\isanewline
+\isakeyword{where}\isanewline
+\ \ {\isachardoublequoteopen}x\ {\isasymapprox}Lang\ y\ {\isasymequiv}\ {\isacharparenleft}x{\isacharcomma}\ y{\isacharparenright}\ {\isasymin}\ {\isacharparenleft}{\isasymapprox}Lang{\isacharparenright}{\isachardoublequoteclose}%
+\begin{isamarkuptext}%
+The very basic scheme to show the finiteness of the partion generated by a language \isa{Lang}
+ is by attaching tags to every string. The set of tags are carfully choosen to make it finite.
+ If it can be proved that strings with the same tag are equivlent with respect \isa{Lang},
+ then the partition given rise by \isa{Lang} must be finite. The reason for this is a lemma
+ in standard library (\isa{finite{\isacharunderscore}imageD}), which says: if the image of an injective
+ function on a set \isa{A} is finite, then \isa{A} is finite. It can be shown that
+ the function obtained by llifting \isa{tag}
+ to the level of equalent classes (i.e. \isa{{\isacharparenleft}{\isacharparenleft}op\ {\isacharbackquote}{\isacharparenright}\ tag{\isacharparenright}}) is injective
+ (by lemma \isa{tag{\isacharunderscore}image{\isacharunderscore}injI}) and the image of this function is finite
+ (with the help of lemma \isa{finite{\isacharunderscore}tag{\isacharunderscore}imageI}).
+
+ BUT, I think this argument can be encapsulated by one lemma instead of the current presentation.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{lemma}\isamarkupfalse%
+\ eq{\isacharunderscore}class{\isacharunderscore}equalI{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}{\isasymlbrakk}X\ {\isasymin}\ UNIV\ {\isacharslash}{\isacharslash}\ {\isasymapprox}lang{\isacharsemicolon}\ Y\ {\isasymin}\ UNIV\ {\isacharslash}{\isacharslash}\ {\isasymapprox}lang{\isacharsemicolon}\ x\ {\isasymin}\ X{\isacharsemicolon}\ y\ {\isasymin}\ Y{\isacharsemicolon}\ x\ {\isasymapprox}lang\ y{\isasymrbrakk}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ {\isasymLongrightarrow}\ X\ {\isacharequal}\ Y{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}quotient{\isacharunderscore}def\ str{\isacharunderscore}eq{\isacharunderscore}rel{\isacharunderscore}def\ str{\isacharunderscore}eq{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ tag{\isacharunderscore}image{\isacharunderscore}injI{\isacharcolon}\isanewline
+\ \ \isakeyword{assumes}\ str{\isacharunderscore}inj{\isacharcolon}\ {\isachardoublequoteopen}{\isasymAnd}\ x\ y{\isachardot}\ tag\ x\ {\isacharequal}\ tag\ {\isacharparenleft}y{\isacharcolon}{\isacharcolon}string{\isacharparenright}\ {\isasymLongrightarrow}\ x\ {\isasymapprox}lang\ y{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{shows}\ {\isachardoublequoteopen}inj{\isacharunderscore}on\ {\isacharparenleft}{\isacharparenleft}op\ {\isacharbackquote}{\isacharparenright}\ tag{\isacharparenright}\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isasymapprox}lang{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+{\isacharminus}\isanewline
+\ \ \isacommand{{\isacharbraceleft}}\isamarkupfalse%
+\ \isacommand{fix}\isamarkupfalse%
+\ X\ Y\isanewline
+\ \ \ \ \isacommand{assume}\isamarkupfalse%
+\ X{\isacharunderscore}in{\isacharcolon}\ {\isachardoublequoteopen}X\ {\isasymin}\ UNIV\ {\isacharslash}{\isacharslash}\ {\isasymapprox}lang{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \isakeyword{and}\ \ Y{\isacharunderscore}in{\isacharcolon}\ {\isachardoublequoteopen}Y\ {\isasymin}\ UNIV\ {\isacharslash}{\isacharslash}\ {\isasymapprox}lang{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \isakeyword{and}\ \ tag{\isacharunderscore}eq{\isacharcolon}\ {\isachardoublequoteopen}tag\ {\isacharbackquote}\ X\ {\isacharequal}\ tag\ {\isacharbackquote}\ Y{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{then}\isamarkupfalse%
+\ \isacommand{obtain}\isamarkupfalse%
+\ x\ y\ \isakeyword{where}\ {\isachardoublequoteopen}x\ {\isasymin}\ X{\isachardoublequoteclose}\ \isakeyword{and}\ {\isachardoublequoteopen}y\ {\isasymin}\ Y{\isachardoublequoteclose}\ \isakeyword{and}\ {\isachardoublequoteopen}tag\ x\ {\isacharequal}\ tag\ y{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \isacommand{unfolding}\isamarkupfalse%
+\ quotient{\isacharunderscore}def\ Image{\isacharunderscore}def\ str{\isacharunderscore}eq{\isacharunderscore}rel{\isacharunderscore}def\ str{\isacharunderscore}eq{\isacharunderscore}def\ image{\isacharunderscore}def\isanewline
+\ \ \ \ \ \ \isacommand{apply}\isamarkupfalse%
+\ simp\ \isacommand{by}\isamarkupfalse%
+\ blast\isanewline
+\ \ \ \ \isacommand{with}\isamarkupfalse%
+\ X{\isacharunderscore}in\ Y{\isacharunderscore}in\ str{\isacharunderscore}inj\isanewline
+\ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}X\ {\isacharequal}\ Y{\isachardoublequoteclose}\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}rule{\isacharunderscore}tac\ eq{\isacharunderscore}class{\isacharunderscore}equalI{\isacharcomma}\ simp{\isacharplus}{\isacharparenright}\isanewline
+\ \ \isacommand{{\isacharbraceright}}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{thus}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{unfolding}\isamarkupfalse%
+\ inj{\isacharunderscore}on{\isacharunderscore}def\ \isacommand{by}\isamarkupfalse%
+\ auto\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ finite{\isacharunderscore}tag{\isacharunderscore}imageI{\isacharcolon}\ \isanewline
+\ \ {\isachardoublequoteopen}finite\ {\isacharparenleft}range\ tag{\isacharparenright}\ {\isasymLongrightarrow}\ finite\ {\isacharparenleft}{\isacharparenleft}{\isacharparenleft}op\ {\isacharbackquote}{\isacharparenright}\ tag{\isacharparenright}\ {\isacharbackquote}\ S{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}rule{\isacharunderscore}tac\ B\ {\isacharequal}\ {\isachardoublequoteopen}Pow\ {\isacharparenleft}tag\ {\isacharbackquote}\ UNIV{\isacharparenright}{\isachardoublequoteclose}\ \isakeyword{in}\ finite{\isacharunderscore}subset{\isacharparenright}\isanewline
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp\ add{\isacharcolon}image{\isacharunderscore}def\ Pow{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isamarkupsubsection{A small theory for list difference%
+}
+\isamarkuptrue%
+%
+\begin{isamarkuptext}%
+The notion of list diffrence is need to make proofs more readable.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{fun}\isamarkupfalse%
+\ list{\isacharunderscore}diff\ {\isacharcolon}{\isacharcolon}\ {\isachardoublequoteopen}{\isacharprime}a\ list\ {\isasymRightarrow}\ {\isacharprime}a\ list\ {\isasymRightarrow}\ {\isacharprime}a\ list{\isachardoublequoteclose}\ {\isacharparenleft}\isakeyword{infix}\ {\isachardoublequoteopen}{\isacharminus}{\isachardoublequoteclose}\ {\isadigit{5}}{\isadigit{1}}{\isacharparenright}\isanewline
+\isakeyword{where}\isanewline
+\ \ {\isachardoublequoteopen}list{\isacharunderscore}diff\ {\isacharbrackleft}{\isacharbrackright}\ \ xs\ {\isacharequal}\ {\isacharbrackleft}{\isacharbrackright}{\isachardoublequoteclose}\ {\isacharbar}\isanewline
+\ \ {\isachardoublequoteopen}list{\isacharunderscore}diff\ {\isacharparenleft}x{\isacharhash}xs{\isacharparenright}\ {\isacharbrackleft}{\isacharbrackright}\ {\isacharequal}\ x{\isacharhash}xs{\isachardoublequoteclose}\ {\isacharbar}\isanewline
+\ \ {\isachardoublequoteopen}list{\isacharunderscore}diff\ {\isacharparenleft}x{\isacharhash}xs{\isacharparenright}\ {\isacharparenleft}y{\isacharhash}ys{\isacharparenright}\ {\isacharequal}\ {\isacharparenleft}if\ x\ {\isacharequal}\ y\ then\ list{\isacharunderscore}diff\ xs\ ys\ else\ {\isacharparenleft}x{\isacharhash}xs{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ {\isacharbrackleft}simp{\isacharbrackright}{\isacharcolon}\ {\isachardoublequoteopen}{\isacharparenleft}x\ {\isacharat}\ y{\isacharparenright}\ {\isacharminus}\ x\ {\isacharequal}\ y{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}induct\ x{\isacharparenright}\isanewline
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}case{\isacharunderscore}tac\ y{\isacharcomma}\ simp{\isacharplus}{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ {\isacharbrackleft}simp{\isacharbrackright}{\isacharcolon}\ {\isachardoublequoteopen}x\ {\isacharminus}\ x\ {\isacharequal}\ {\isacharbrackleft}{\isacharbrackright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}induct\ x{\isacharcomma}\ auto{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ {\isacharbrackleft}simp{\isacharbrackright}{\isacharcolon}\ {\isachardoublequoteopen}x\ {\isacharequal}\ xa\ {\isacharat}\ y\ {\isasymLongrightarrow}\ x\ {\isacharminus}\ xa\ {\isacharequal}\ y\ {\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}induct\ x{\isacharcomma}\ auto{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ {\isacharbrackleft}simp{\isacharbrackright}{\isacharcolon}\ {\isachardoublequoteopen}x\ {\isacharminus}\ {\isacharbrackleft}{\isacharbrackright}\ {\isacharequal}\ x{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}induct\ x{\isacharcomma}\ auto{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ {\isacharbrackleft}simp{\isacharbrackright}{\isacharcolon}\ {\isachardoublequoteopen}{\isacharparenleft}x\ {\isacharminus}\ y\ {\isacharequal}\ {\isacharbrackleft}{\isacharbrackright}{\isacharparenright}\ {\isasymLongrightarrow}\ {\isacharparenleft}x\ {\isasymle}\ y{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+{\isacharminus}\ \ \ \isanewline
+\ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isasymexists}xa{\isachardot}\ x\ {\isacharequal}\ xa\ {\isacharat}\ {\isacharparenleft}x\ {\isacharminus}\ y{\isacharparenright}\ {\isasymand}\ xa\ {\isasymle}\ y{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}rule\ list{\isacharunderscore}diff{\isachardot}induct{\isacharbrackleft}of\ {\isacharunderscore}\ x\ y{\isacharbrackright}{\isacharcomma}\ simp{\isacharplus}{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}clarsimp{\isacharcomma}\ rule{\isacharunderscore}tac\ x\ {\isacharequal}\ {\isachardoublequoteopen}y\ {\isacharhash}\ xa{\isachardoublequoteclose}\ \isakeyword{in}\ exI{\isacharcomma}\ simp{\isacharplus}{\isacharparenright}\isanewline
+\ \ \isacommand{thus}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isacharparenleft}x\ {\isacharminus}\ y\ {\isacharequal}\ {\isacharbrackleft}{\isacharbrackright}{\isacharparenright}\ {\isasymLongrightarrow}\ {\isacharparenleft}x\ {\isasymle}\ y{\isacharparenright}{\isachardoublequoteclose}\ \isacommand{by}\isamarkupfalse%
+\ simp\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ diff{\isacharunderscore}prefix{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}{\isasymlbrakk}c\ {\isasymle}\ a\ {\isacharminus}\ b{\isacharsemicolon}\ b\ {\isasymle}\ a{\isasymrbrakk}\ {\isasymLongrightarrow}\ b\ {\isacharat}\ c\ {\isasymle}\ a{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ elim{\isacharcolon}prefixE{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ diff{\isacharunderscore}diff{\isacharunderscore}appd{\isacharcolon}\ \isanewline
+\ \ {\isachardoublequoteopen}{\isasymlbrakk}c\ {\isacharless}\ a\ {\isacharminus}\ b{\isacharsemicolon}\ b\ {\isacharless}\ a{\isasymrbrakk}\ {\isasymLongrightarrow}\ {\isacharparenleft}a\ {\isacharminus}\ b{\isacharparenright}\ {\isacharminus}\ c\ {\isacharequal}\ a\ {\isacharminus}\ {\isacharparenleft}b\ {\isacharat}\ c{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}clarsimp\ simp{\isacharcolon}strict{\isacharunderscore}prefix{\isacharunderscore}def{\isacharparenright}\isanewline
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}drule\ diff{\isacharunderscore}prefix{\isacharcomma}\ auto\ elim{\isacharcolon}prefixE{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ app{\isacharunderscore}eq{\isacharunderscore}cases{\isacharbrackleft}rule{\isacharunderscore}format{\isacharbrackright}{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}{\isasymforall}\ x\ {\isachardot}\ x\ {\isacharat}\ y\ {\isacharequal}\ m\ {\isacharat}\ n\ {\isasymlongrightarrow}\ {\isacharparenleft}x\ {\isasymle}\ m\ {\isasymor}\ m\ {\isasymle}\ x{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}induct\ y{\isacharcomma}\ simp{\isacharparenright}\isanewline
+\isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}clarify{\isacharcomma}\ drule{\isacharunderscore}tac\ x\ {\isacharequal}\ {\isachardoublequoteopen}x\ {\isacharat}\ {\isacharbrackleft}a{\isacharbrackright}{\isachardoublequoteclose}\ \isakeyword{in}\ spec{\isacharparenright}\isanewline
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}clarsimp{\isacharcomma}\ auto\ simp{\isacharcolon}prefix{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ app{\isacharunderscore}eq{\isacharunderscore}dest{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}x\ {\isacharat}\ y\ {\isacharequal}\ m\ {\isacharat}\ n\ {\isasymLongrightarrow}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ {\isacharparenleft}x\ {\isasymle}\ m\ {\isasymand}\ {\isacharparenleft}m\ {\isacharminus}\ x{\isacharparenright}\ {\isacharat}\ n\ {\isacharequal}\ y{\isacharparenright}\ {\isasymor}\ {\isacharparenleft}m\ {\isasymle}\ x\ {\isasymand}\ {\isacharparenleft}x\ {\isacharminus}\ m{\isacharparenright}\ {\isacharat}\ y\ {\isacharequal}\ n{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}frule{\isacharunderscore}tac\ app{\isacharunderscore}eq{\isacharunderscore}cases{\isacharcomma}\ auto\ elim{\isacharcolon}prefixE{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isamarkupsubsection{Lemmas for basic cases%
+}
+\isamarkuptrue%
+%
+\begin{isamarkuptext}%
+The the final result of this direction is in \isa{easier{\isacharunderscore}direction}, which
+ is an induction on the structure of regular expressions. There is one case
+ for each regular expression operator. For basic operators such as \isa{NULL{\isacharcomma}\ EMPTY{\isacharcomma}\ CHAR\ c},
+ the finiteness of their language partition can be established directly with no need
+ of taggiing. This section contains several technical lemma for these base cases.
+
+ The inductive cases involve operators \isa{ALT{\isacharcomma}\ SEQ} and \isa{STAR}.
+ Tagging functions need to be defined individually for each of them. There will be one
+ dedicated section for each of these cases, and each section goes virtually the same way:
+ gives definition of the tagging function and prove that strings
+ with the same tag are equivalent.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{lemma}\isamarkupfalse%
+\ quot{\isacharunderscore}empty{\isacharunderscore}subset{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}UNIV\ {\isacharslash}{\isacharslash}\ {\isacharparenleft}{\isasymapprox}{\isacharbraceleft}{\isacharbrackleft}{\isacharbrackright}{\isacharbraceright}{\isacharparenright}\ {\isasymsubseteq}\ {\isacharbraceleft}{\isacharbraceleft}{\isacharbrackleft}{\isacharbrackright}{\isacharbraceright}{\isacharcomma}\ UNIV\ {\isacharminus}\ {\isacharbraceleft}{\isacharbrackleft}{\isacharbrackright}{\isacharbraceright}{\isacharbraceright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{fix}\isamarkupfalse%
+\ x\isanewline
+\ \ \isacommand{assume}\isamarkupfalse%
+\ {\isachardoublequoteopen}x\ {\isasymin}\ UNIV\ {\isacharslash}{\isacharslash}\ {\isasymapprox}{\isacharbraceleft}{\isacharbrackleft}{\isacharbrackright}{\isacharbraceright}{\isachardoublequoteclose}\isanewline
+\ \ \isacommand{then}\isamarkupfalse%
+\ \isacommand{obtain}\isamarkupfalse%
+\ y\ \isakeyword{where}\ h{\isacharcolon}\ {\isachardoublequoteopen}x\ {\isacharequal}\ {\isacharbraceleft}z{\isachardot}\ {\isacharparenleft}y{\isacharcomma}\ z{\isacharparenright}\ {\isasymin}\ {\isasymapprox}{\isacharbraceleft}{\isacharbrackleft}{\isacharbrackright}{\isacharbraceright}{\isacharbraceright}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \isacommand{unfolding}\isamarkupfalse%
+\ quotient{\isacharunderscore}def\ Image{\isacharunderscore}def\ \isacommand{by}\isamarkupfalse%
+\ blast\isanewline
+\ \ \isacommand{show}\isamarkupfalse%
+\ {\isachardoublequoteopen}x\ {\isasymin}\ {\isacharbraceleft}{\isacharbraceleft}{\isacharbrackleft}{\isacharbrackright}{\isacharbraceright}{\isacharcomma}\ UNIV\ {\isacharminus}\ {\isacharbraceleft}{\isacharbrackleft}{\isacharbrackright}{\isacharbraceright}{\isacharbraceright}{\isachardoublequoteclose}\ \isanewline
+\ \ \isacommand{proof}\isamarkupfalse%
+\ {\isacharparenleft}cases\ {\isachardoublequoteopen}y\ {\isacharequal}\ {\isacharbrackleft}{\isacharbrackright}{\isachardoublequoteclose}{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{case}\isamarkupfalse%
+\ True\ \isacommand{with}\isamarkupfalse%
+\ h\isanewline
+\ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}x\ {\isacharequal}\ {\isacharbraceleft}{\isacharbrackleft}{\isacharbrackright}{\isacharbraceright}{\isachardoublequoteclose}\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}str{\isacharunderscore}eq{\isacharunderscore}rel{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{thus}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ simp\isanewline
+\ \ \isacommand{next}\isamarkupfalse%
+\isanewline
+\ \ \ \ \isacommand{case}\isamarkupfalse%
+\ False\ \isacommand{with}\isamarkupfalse%
+\ h\isanewline
+\ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}x\ {\isacharequal}\ UNIV\ {\isacharminus}\ {\isacharbraceleft}{\isacharbrackleft}{\isacharbrackright}{\isacharbraceright}{\isachardoublequoteclose}\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}str{\isacharunderscore}eq{\isacharunderscore}rel{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{thus}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ simp\isanewline
+\ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ quot{\isacharunderscore}char{\isacharunderscore}subset{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}UNIV\ {\isacharslash}{\isacharslash}\ {\isacharparenleft}{\isasymapprox}{\isacharbraceleft}{\isacharbrackleft}c{\isacharbrackright}{\isacharbraceright}{\isacharparenright}\ {\isasymsubseteq}\ {\isacharbraceleft}{\isacharbraceleft}{\isacharbrackleft}{\isacharbrackright}{\isacharbraceright}{\isacharcomma}{\isacharbraceleft}{\isacharbrackleft}c{\isacharbrackright}{\isacharbraceright}{\isacharcomma}\ UNIV\ {\isacharminus}\ {\isacharbraceleft}{\isacharbrackleft}{\isacharbrackright}{\isacharcomma}\ {\isacharbrackleft}c{\isacharbrackright}{\isacharbraceright}{\isacharbraceright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+\ \isanewline
+\ \ \isacommand{fix}\isamarkupfalse%
+\ x\ \isanewline
+\ \ \isacommand{assume}\isamarkupfalse%
+\ {\isachardoublequoteopen}x\ {\isasymin}\ UNIV\ {\isacharslash}{\isacharslash}\ {\isasymapprox}{\isacharbraceleft}{\isacharbrackleft}c{\isacharbrackright}{\isacharbraceright}{\isachardoublequoteclose}\isanewline
+\ \ \isacommand{then}\isamarkupfalse%
+\ \isacommand{obtain}\isamarkupfalse%
+\ y\ \isakeyword{where}\ h{\isacharcolon}\ {\isachardoublequoteopen}x\ {\isacharequal}\ {\isacharbraceleft}z{\isachardot}\ {\isacharparenleft}y{\isacharcomma}\ z{\isacharparenright}\ {\isasymin}\ {\isasymapprox}{\isacharbraceleft}{\isacharbrackleft}c{\isacharbrackright}{\isacharbraceright}{\isacharbraceright}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \isacommand{unfolding}\isamarkupfalse%
+\ quotient{\isacharunderscore}def\ Image{\isacharunderscore}def\ \isacommand{by}\isamarkupfalse%
+\ blast\isanewline
+\ \ \isacommand{show}\isamarkupfalse%
+\ {\isachardoublequoteopen}x\ {\isasymin}\ {\isacharbraceleft}{\isacharbraceleft}{\isacharbrackleft}{\isacharbrackright}{\isacharbraceright}{\isacharcomma}{\isacharbraceleft}{\isacharbrackleft}c{\isacharbrackright}{\isacharbraceright}{\isacharcomma}\ UNIV\ {\isacharminus}\ {\isacharbraceleft}{\isacharbrackleft}{\isacharbrackright}{\isacharcomma}\ {\isacharbrackleft}c{\isacharbrackright}{\isacharbraceright}{\isacharbraceright}{\isachardoublequoteclose}\isanewline
+\ \ \isacommand{proof}\isamarkupfalse%
+\ {\isacharminus}\isanewline
+\ \ \ \ \isacommand{{\isacharbraceleft}}\isamarkupfalse%
+\ \isacommand{assume}\isamarkupfalse%
+\ {\isachardoublequoteopen}y\ {\isacharequal}\ {\isacharbrackleft}{\isacharbrackright}{\isachardoublequoteclose}\ \isacommand{hence}\isamarkupfalse%
+\ {\isachardoublequoteopen}x\ {\isacharequal}\ {\isacharbraceleft}{\isacharbrackleft}{\isacharbrackright}{\isacharbraceright}{\isachardoublequoteclose}\ \isacommand{using}\isamarkupfalse%
+\ h\ \isanewline
+\ \ \ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}str{\isacharunderscore}eq{\isacharunderscore}rel{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{{\isacharbraceright}}\isamarkupfalse%
+\ \isacommand{moreover}\isamarkupfalse%
+\ \isacommand{{\isacharbraceleft}}\isamarkupfalse%
+\isanewline
+\ \ \ \ \ \ \isacommand{assume}\isamarkupfalse%
+\ {\isachardoublequoteopen}y\ {\isacharequal}\ {\isacharbrackleft}c{\isacharbrackright}{\isachardoublequoteclose}\ \isacommand{hence}\isamarkupfalse%
+\ {\isachardoublequoteopen}x\ {\isacharequal}\ {\isacharbraceleft}{\isacharbrackleft}c{\isacharbrackright}{\isacharbraceright}{\isachardoublequoteclose}\ \isacommand{using}\isamarkupfalse%
+\ h\ \isanewline
+\ \ \ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ dest{\isacharbang}{\isacharcolon}spec{\isacharbrackleft}\isakeyword{where}\ x\ {\isacharequal}\ {\isachardoublequoteopen}{\isacharbrackleft}{\isacharbrackright}{\isachardoublequoteclose}{\isacharbrackright}\ simp{\isacharcolon}str{\isacharunderscore}eq{\isacharunderscore}rel{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{{\isacharbraceright}}\isamarkupfalse%
+\ \isacommand{moreover}\isamarkupfalse%
+\ \isacommand{{\isacharbraceleft}}\isamarkupfalse%
+\isanewline
+\ \ \ \ \ \ \isacommand{assume}\isamarkupfalse%
+\ {\isachardoublequoteopen}y\ {\isasymnoteq}\ {\isacharbrackleft}{\isacharbrackright}{\isachardoublequoteclose}\ \isakeyword{and}\ {\isachardoublequoteopen}y\ {\isasymnoteq}\ {\isacharbrackleft}c{\isacharbrackright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \isacommand{hence}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isasymforall}\ z{\isachardot}\ {\isacharparenleft}y\ {\isacharat}\ z{\isacharparenright}\ {\isasymnoteq}\ {\isacharbrackleft}c{\isacharbrackright}{\isachardoublequoteclose}\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}case{\isacharunderscore}tac\ y{\isacharcomma}\ auto{\isacharparenright}\isanewline
+\ \ \ \ \ \ \isacommand{moreover}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isasymAnd}\ p{\isachardot}\ {\isacharparenleft}p\ {\isasymnoteq}\ {\isacharbrackleft}{\isacharbrackright}\ {\isasymand}\ p\ {\isasymnoteq}\ {\isacharbrackleft}c{\isacharbrackright}{\isacharparenright}\ {\isacharequal}\ {\isacharparenleft}{\isasymforall}\ q{\isachardot}\ p\ {\isacharat}\ q\ {\isasymnoteq}\ {\isacharbrackleft}c{\isacharbrackright}{\isacharparenright}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}case{\isacharunderscore}tac\ p{\isacharcomma}\ auto{\isacharparenright}\isanewline
+\ \ \ \ \ \ \isacommand{ultimately}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}x\ {\isacharequal}\ UNIV\ {\isacharminus}\ {\isacharbraceleft}{\isacharbrackleft}{\isacharbrackright}{\isacharcomma}{\isacharbrackleft}c{\isacharbrackright}{\isacharbraceright}{\isachardoublequoteclose}\ \isacommand{using}\isamarkupfalse%
+\ h\isanewline
+\ \ \ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp\ add{\isacharcolon}str{\isacharunderscore}eq{\isacharunderscore}rel{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{{\isacharbraceright}}\isamarkupfalse%
+\ \isacommand{ultimately}\isamarkupfalse%
+\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ blast\isanewline
+\ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isamarkupsubsection{The case for \isa{SEQ}%
+}
+\isamarkuptrue%
+\isacommand{definition}\isamarkupfalse%
+\ \isanewline
+\ \ {\isachardoublequoteopen}tag{\isacharunderscore}str{\isacharunderscore}SEQ\ L\isactrlisub {\isadigit{1}}\ L\isactrlisub {\isadigit{2}}\ x\ {\isasymequiv}\ \isanewline
+\ \ \ \ \ \ \ {\isacharparenleft}{\isacharparenleft}{\isasymapprox}L\isactrlisub {\isadigit{1}}{\isacharparenright}\ {\isacharbackquote}{\isacharbackquote}\ {\isacharbraceleft}x{\isacharbraceright}{\isacharcomma}\ {\isacharbraceleft}{\isacharparenleft}{\isasymapprox}L\isactrlisub {\isadigit{2}}{\isacharparenright}\ {\isacharbackquote}{\isacharbackquote}\ {\isacharbraceleft}x\ {\isacharminus}\ xa{\isacharbraceright}{\isacharbar}\ xa{\isachardot}\ \ xa\ {\isasymle}\ x\ {\isasymand}\ xa\ {\isasymin}\ L\isactrlisub {\isadigit{1}}{\isacharbraceright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ tag{\isacharunderscore}str{\isacharunderscore}seq{\isacharunderscore}range{\isacharunderscore}finite{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}{\isasymlbrakk}finite\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isasymapprox}L\isactrlisub {\isadigit{1}}{\isacharparenright}{\isacharsemicolon}\ finite\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isasymapprox}L\isactrlisub {\isadigit{2}}{\isacharparenright}{\isasymrbrakk}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ {\isasymLongrightarrow}\ finite\ {\isacharparenleft}range\ {\isacharparenleft}tag{\isacharunderscore}str{\isacharunderscore}SEQ\ L\isactrlisub {\isadigit{1}}\ L\isactrlisub {\isadigit{2}}{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}rule{\isacharunderscore}tac\ B\ {\isacharequal}\ {\isachardoublequoteopen}{\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isasymapprox}L\isactrlisub {\isadigit{1}}{\isacharparenright}\ {\isasymtimes}\ {\isacharparenleft}Pow\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isasymapprox}L\isactrlisub {\isadigit{2}}{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\ \isakeyword{in}\ finite{\isacharunderscore}subset{\isacharparenright}\isanewline
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}tag{\isacharunderscore}str{\isacharunderscore}SEQ{\isacharunderscore}def\ Image{\isacharunderscore}def\ quotient{\isacharunderscore}def\ split{\isacharcolon}if{\isacharunderscore}splits{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ append{\isacharunderscore}seq{\isacharunderscore}elim{\isacharcolon}\isanewline
+\ \ \isakeyword{assumes}\ {\isachardoublequoteopen}x\ {\isacharat}\ y\ {\isasymin}\ L\isactrlisub {\isadigit{1}}\ {\isacharsemicolon}{\isacharsemicolon}\ L\isactrlisub {\isadigit{2}}{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{shows}\ {\isachardoublequoteopen}{\isacharparenleft}{\isasymexists}\ xa\ {\isasymle}\ x{\isachardot}\ xa\ {\isasymin}\ L\isactrlisub {\isadigit{1}}\ {\isasymand}\ {\isacharparenleft}x\ {\isacharminus}\ xa{\isacharparenright}\ {\isacharat}\ y\ {\isasymin}\ L\isactrlisub {\isadigit{2}}{\isacharparenright}\ {\isasymor}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ {\isacharparenleft}{\isasymexists}\ ya\ {\isasymle}\ y{\isachardot}\ {\isacharparenleft}x\ {\isacharat}\ ya{\isacharparenright}\ {\isasymin}\ L\isactrlisub {\isadigit{1}}\ {\isasymand}\ {\isacharparenleft}y\ {\isacharminus}\ ya{\isacharparenright}\ {\isasymin}\ L\isactrlisub {\isadigit{2}}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+{\isacharminus}\isanewline
+\ \ \isacommand{from}\isamarkupfalse%
+\ assms\ \isacommand{obtain}\isamarkupfalse%
+\ s\isactrlisub {\isadigit{1}}\ s\isactrlisub {\isadigit{2}}\ \isanewline
+\ \ \ \ \isakeyword{where}\ {\isachardoublequoteopen}x\ {\isacharat}\ y\ {\isacharequal}\ s\isactrlisub {\isadigit{1}}\ {\isacharat}\ s\isactrlisub {\isadigit{2}}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \isakeyword{and}\ in{\isacharunderscore}seq{\isacharcolon}\ {\isachardoublequoteopen}s\isactrlisub {\isadigit{1}}\ {\isasymin}\ L\isactrlisub {\isadigit{1}}\ {\isasymand}\ s\isactrlisub {\isadigit{2}}\ {\isasymin}\ L\isactrlisub {\isadigit{2}}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}Seq{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \isacommand{hence}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isacharparenleft}x\ {\isasymle}\ s\isactrlisub {\isadigit{1}}\ {\isasymand}\ {\isacharparenleft}s\isactrlisub {\isadigit{1}}\ {\isacharminus}\ x{\isacharparenright}\ {\isacharat}\ s\isactrlisub {\isadigit{2}}\ {\isacharequal}\ y{\isacharparenright}\ {\isasymor}\ {\isacharparenleft}s\isactrlisub {\isadigit{1}}\ {\isasymle}\ x\ {\isasymand}\ {\isacharparenleft}x\ {\isacharminus}\ s\isactrlisub {\isadigit{1}}{\isacharparenright}\ {\isacharat}\ y\ {\isacharequal}\ s\isactrlisub {\isadigit{2}}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{using}\isamarkupfalse%
+\ app{\isacharunderscore}eq{\isacharunderscore}dest\ \isacommand{by}\isamarkupfalse%
+\ auto\isanewline
+\ \ \isacommand{moreover}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isasymlbrakk}x\ {\isasymle}\ s\isactrlisub {\isadigit{1}}{\isacharsemicolon}\ {\isacharparenleft}s\isactrlisub {\isadigit{1}}\ {\isacharminus}\ x{\isacharparenright}\ {\isacharat}\ s\isactrlisub {\isadigit{2}}\ {\isacharequal}\ y{\isasymrbrakk}\ {\isasymLongrightarrow}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ {\isasymexists}\ ya\ {\isasymle}\ y{\isachardot}\ {\isacharparenleft}x\ {\isacharat}\ ya{\isacharparenright}\ {\isasymin}\ L\isactrlisub {\isadigit{1}}\ {\isasymand}\ {\isacharparenleft}y\ {\isacharminus}\ ya{\isacharparenright}\ {\isasymin}\ L\isactrlisub {\isadigit{2}}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \isacommand{using}\isamarkupfalse%
+\ in{\isacharunderscore}seq\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}rule{\isacharunderscore}tac\ x\ {\isacharequal}\ {\isachardoublequoteopen}s\isactrlisub {\isadigit{1}}\ {\isacharminus}\ x{\isachardoublequoteclose}\ \isakeyword{in}\ exI{\isacharcomma}\ auto\ elim{\isacharcolon}prefixE{\isacharparenright}\isanewline
+\ \ \isacommand{moreover}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isasymlbrakk}s\isactrlisub {\isadigit{1}}\ {\isasymle}\ x{\isacharsemicolon}\ {\isacharparenleft}x\ {\isacharminus}\ s\isactrlisub {\isadigit{1}}{\isacharparenright}\ {\isacharat}\ y\ {\isacharequal}\ s\isactrlisub {\isadigit{2}}{\isasymrbrakk}\ {\isasymLongrightarrow}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ {\isasymexists}\ xa\ {\isasymle}\ x{\isachardot}\ xa\ {\isasymin}\ L\isactrlisub {\isadigit{1}}\ {\isasymand}\ {\isacharparenleft}x\ {\isacharminus}\ xa{\isacharparenright}\ {\isacharat}\ y\ {\isasymin}\ L\isactrlisub {\isadigit{2}}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \isacommand{using}\isamarkupfalse%
+\ in{\isacharunderscore}seq\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}rule{\isacharunderscore}tac\ x\ {\isacharequal}\ s\isactrlisub {\isadigit{1}}\ \isakeyword{in}\ exI{\isacharcomma}\ auto{\isacharparenright}\isanewline
+\ \ \isacommand{ultimately}\isamarkupfalse%
+\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ blast\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ tag{\isacharunderscore}str{\isacharunderscore}SEQ{\isacharunderscore}injI{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}tag{\isacharunderscore}str{\isacharunderscore}SEQ\ L\isactrlisub {\isadigit{1}}\ L\isactrlisub {\isadigit{2}}\ m\ {\isacharequal}\ tag{\isacharunderscore}str{\isacharunderscore}SEQ\ L\isactrlisub {\isadigit{1}}\ L\isactrlisub {\isadigit{2}}\ n\ {\isasymLongrightarrow}\ m\ {\isasymapprox}{\isacharparenleft}L\isactrlisub {\isadigit{1}}\ {\isacharsemicolon}{\isacharsemicolon}\ L\isactrlisub {\isadigit{2}}{\isacharparenright}\ n{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+{\isacharminus}\isanewline
+\ \ \isacommand{{\isacharbraceleft}}\isamarkupfalse%
+\ \isacommand{fix}\isamarkupfalse%
+\ x\ y\ z\isanewline
+\ \ \ \ \isacommand{assume}\isamarkupfalse%
+\ xz{\isacharunderscore}in{\isacharunderscore}seq{\isacharcolon}\ {\isachardoublequoteopen}x\ {\isacharat}\ z\ {\isasymin}\ L\isactrlisub {\isadigit{1}}\ {\isacharsemicolon}{\isacharsemicolon}\ L\isactrlisub {\isadigit{2}}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isakeyword{and}\ tag{\isacharunderscore}xy{\isacharcolon}\ {\isachardoublequoteopen}tag{\isacharunderscore}str{\isacharunderscore}SEQ\ L\isactrlisub {\isadigit{1}}\ L\isactrlisub {\isadigit{2}}\ x\ {\isacharequal}\ tag{\isacharunderscore}str{\isacharunderscore}SEQ\ L\isactrlisub {\isadigit{1}}\ L\isactrlisub {\isadigit{2}}\ y{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{have}\isamarkupfalse%
+{\isachardoublequoteopen}y\ {\isacharat}\ z\ {\isasymin}\ L\isactrlisub {\isadigit{1}}\ {\isacharsemicolon}{\isacharsemicolon}\ L\isactrlisub {\isadigit{2}}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \isacommand{proof}\isamarkupfalse%
+{\isacharminus}\isanewline
+\ \ \ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isacharparenleft}{\isasymexists}\ xa\ {\isasymle}\ x{\isachardot}\ xa\ {\isasymin}\ L\isactrlisub {\isadigit{1}}\ {\isasymand}\ {\isacharparenleft}x\ {\isacharminus}\ xa{\isacharparenright}\ {\isacharat}\ z\ {\isasymin}\ L\isactrlisub {\isadigit{2}}{\isacharparenright}\ {\isasymor}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ {\isacharparenleft}{\isasymexists}\ za\ {\isasymle}\ z{\isachardot}\ {\isacharparenleft}x\ {\isacharat}\ za{\isacharparenright}\ {\isasymin}\ L\isactrlisub {\isadigit{1}}\ {\isasymand}\ {\isacharparenleft}z\ {\isacharminus}\ za{\isacharparenright}\ {\isasymin}\ L\isactrlisub {\isadigit{2}}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \ \ \isacommand{using}\isamarkupfalse%
+\ xz{\isacharunderscore}in{\isacharunderscore}seq\ append{\isacharunderscore}seq{\isacharunderscore}elim\ \isacommand{by}\isamarkupfalse%
+\ simp\isanewline
+\ \ \ \ \ \ \isacommand{moreover}\isamarkupfalse%
+\ \isacommand{{\isacharbraceleft}}\isamarkupfalse%
+\isanewline
+\ \ \ \ \ \ \ \ \isacommand{fix}\isamarkupfalse%
+\ xa\isanewline
+\ \ \ \ \ \ \ \ \isacommand{assume}\isamarkupfalse%
+\ h{\isadigit{1}}{\isacharcolon}\ {\isachardoublequoteopen}xa\ {\isasymle}\ x{\isachardoublequoteclose}\ \isakeyword{and}\ h{\isadigit{2}}{\isacharcolon}\ {\isachardoublequoteopen}xa\ {\isasymin}\ L\isactrlisub {\isadigit{1}}{\isachardoublequoteclose}\ \isakeyword{and}\ h{\isadigit{3}}{\isacharcolon}\ {\isachardoublequoteopen}{\isacharparenleft}x\ {\isacharminus}\ xa{\isacharparenright}\ {\isacharat}\ z\ {\isasymin}\ L\isactrlisub {\isadigit{2}}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \ \ \isacommand{obtain}\isamarkupfalse%
+\ ya\ \isakeyword{where}\ {\isachardoublequoteopen}ya\ {\isasymle}\ y{\isachardoublequoteclose}\ \isakeyword{and}\ {\isachardoublequoteopen}ya\ {\isasymin}\ L\isactrlisub {\isadigit{1}}{\isachardoublequoteclose}\ \isakeyword{and}\ {\isachardoublequoteopen}{\isacharparenleft}y\ {\isacharminus}\ ya{\isacharparenright}\ {\isacharat}\ z\ {\isasymin}\ L\isactrlisub {\isadigit{2}}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \ \ \ \ \isacommand{proof}\isamarkupfalse%
+\ {\isacharminus}\isanewline
+\ \ \ \ \ \ \ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isasymexists}\ ya{\isachardot}\ \ ya\ {\isasymle}\ y\ {\isasymand}\ ya\ {\isasymin}\ L\isactrlisub {\isadigit{1}}\ {\isasymand}\ {\isacharparenleft}x\ {\isacharminus}\ xa{\isacharparenright}\ {\isasymapprox}L\isactrlisub {\isadigit{2}}\ {\isacharparenleft}y\ {\isacharminus}\ ya{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \ \ \ \ \isacommand{proof}\isamarkupfalse%
+\ {\isacharminus}\isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isacharbraceleft}{\isasymapprox}L\isactrlisub {\isadigit{2}}\ {\isacharbackquote}{\isacharbackquote}\ {\isacharbraceleft}x\ {\isacharminus}\ xa{\isacharbraceright}\ {\isacharbar}xa{\isachardot}\ xa\ {\isasymle}\ x\ {\isasymand}\ xa\ {\isasymin}\ L\isactrlisub {\isadigit{1}}{\isacharbraceright}\ {\isacharequal}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ {\isacharbraceleft}{\isasymapprox}L\isactrlisub {\isadigit{2}}\ {\isacharbackquote}{\isacharbackquote}\ {\isacharbraceleft}y\ {\isacharminus}\ xa{\isacharbraceright}\ {\isacharbar}xa{\isachardot}\ xa\ {\isasymle}\ y\ {\isasymand}\ xa\ {\isasymin}\ L\isactrlisub {\isadigit{1}}{\isacharbraceright}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ {\isacharparenleft}\isakeyword{is}\ {\isachardoublequoteopen}{\isacharquery}Left\ {\isacharequal}\ {\isacharquery}Right{\isachardoublequoteclose}{\isacharparenright}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \isacommand{using}\isamarkupfalse%
+\ h{\isadigit{1}}\ tag{\isacharunderscore}xy\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}tag{\isacharunderscore}str{\isacharunderscore}SEQ{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \isacommand{moreover}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isasymapprox}L\isactrlisub {\isadigit{2}}\ {\isacharbackquote}{\isacharbackquote}\ {\isacharbraceleft}x\ {\isacharminus}\ xa{\isacharbraceright}\ {\isasymin}\ {\isacharquery}Left{\isachardoublequoteclose}\ \isacommand{using}\isamarkupfalse%
+\ h{\isadigit{1}}\ h{\isadigit{2}}\ \isacommand{by}\isamarkupfalse%
+\ auto\isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \isacommand{ultimately}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isasymapprox}L\isactrlisub {\isadigit{2}}\ {\isacharbackquote}{\isacharbackquote}\ {\isacharbraceleft}x\ {\isacharminus}\ xa{\isacharbraceright}\ {\isasymin}\ {\isacharquery}Right{\isachardoublequoteclose}\ \isacommand{by}\isamarkupfalse%
+\ simp\isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \isacommand{thus}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}Image{\isacharunderscore}def\ str{\isacharunderscore}eq{\isacharunderscore}rel{\isacharunderscore}def\ str{\isacharunderscore}eq{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \ \ \ \ \ \ \ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\ \ \ \ \ \ \ \ \ \ \isacommand{with}\isamarkupfalse%
+\ prems\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}str{\isacharunderscore}eq{\isacharunderscore}rel{\isacharunderscore}def\ str{\isacharunderscore}eq{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \ \ \ \ \ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\ \ \ \ \ \ \ \ \isacommand{hence}\isamarkupfalse%
+\ {\isachardoublequoteopen}y\ {\isacharat}\ z\ {\isasymin}\ L\isactrlisub {\isadigit{1}}\ {\isacharsemicolon}{\isacharsemicolon}\ L\isactrlisub {\isadigit{2}}{\isachardoublequoteclose}\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}erule{\isacharunderscore}tac\ prefixE{\isacharcomma}\ auto\ simp{\isacharcolon}Seq{\isacharunderscore}def{\isacharparenright}\ \ \ \ \ \ \ \ \ \ \isanewline
+\ \ \ \ \ \ \isacommand{{\isacharbraceright}}\isamarkupfalse%
+\ \isacommand{moreover}\isamarkupfalse%
+\ \isacommand{{\isacharbraceleft}}\isamarkupfalse%
+\isanewline
+\ \ \ \ \ \ \ \ \isacommand{fix}\isamarkupfalse%
+\ za\isanewline
+\ \ \ \ \ \ \ \ \isacommand{assume}\isamarkupfalse%
+\ h{\isadigit{1}}{\isacharcolon}\ {\isachardoublequoteopen}za\ {\isasymle}\ z{\isachardoublequoteclose}\ \isakeyword{and}\ h{\isadigit{2}}{\isacharcolon}\ {\isachardoublequoteopen}{\isacharparenleft}x\ {\isacharat}\ za{\isacharparenright}\ {\isasymin}\ L\isactrlisub {\isadigit{1}}{\isachardoublequoteclose}\ \isakeyword{and}\ h{\isadigit{3}}{\isacharcolon}\ {\isachardoublequoteopen}z\ {\isacharminus}\ za\ {\isasymin}\ L\isactrlisub {\isadigit{2}}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \ \ \isacommand{hence}\isamarkupfalse%
+\ {\isachardoublequoteopen}y\ {\isacharat}\ za\ {\isasymin}\ L\isactrlisub {\isadigit{1}}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \ \ \isacommand{proof}\isamarkupfalse%
+{\isacharminus}\isanewline
+\ \ \ \ \ \ \ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isasymapprox}L\isactrlisub {\isadigit{1}}\ {\isacharbackquote}{\isacharbackquote}\ {\isacharbraceleft}x{\isacharbraceright}\ {\isacharequal}\ {\isasymapprox}L\isactrlisub {\isadigit{1}}\ {\isacharbackquote}{\isacharbackquote}\ {\isacharbraceleft}y{\isacharbraceright}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \isacommand{using}\isamarkupfalse%
+\ h{\isadigit{1}}\ tag{\isacharunderscore}xy\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}tag{\isacharunderscore}str{\isacharunderscore}SEQ{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \ \ \ \ \ \ \ \ \isacommand{with}\isamarkupfalse%
+\ h{\isadigit{2}}\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}Image{\isacharunderscore}def\ str{\isacharunderscore}eq{\isacharunderscore}rel{\isacharunderscore}def\ str{\isacharunderscore}eq{\isacharunderscore}def{\isacharparenright}\ \isanewline
+\ \ \ \ \ \ \ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\ \ \ \ \ \ \ \ \isacommand{with}\isamarkupfalse%
+\ h{\isadigit{1}}\ h{\isadigit{3}}\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}y\ {\isacharat}\ z\ {\isasymin}\ L\isactrlisub {\isadigit{1}}\ {\isacharsemicolon}{\isacharsemicolon}\ L\isactrlisub {\isadigit{2}}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}drule{\isacharunderscore}tac\ A\ {\isacharequal}\ L\isactrlisub {\isadigit{1}}\ \isakeyword{in}\ seq{\isacharunderscore}intro{\isacharcomma}\ auto\ elim{\isacharcolon}prefixE{\isacharparenright}\isanewline
+\ \ \ \ \ \ \isacommand{{\isacharbraceright}}\isamarkupfalse%
+\isanewline
+\ \ \ \ \ \ \isacommand{ultimately}\isamarkupfalse%
+\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ blast\isanewline
+\ \ \ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{{\isacharbraceright}}\isamarkupfalse%
+\ \isacommand{thus}\isamarkupfalse%
+\ {\isachardoublequoteopen}tag{\isacharunderscore}str{\isacharunderscore}SEQ\ L\isactrlisub {\isadigit{1}}\ L\isactrlisub {\isadigit{2}}\ m\ {\isacharequal}\ tag{\isacharunderscore}str{\isacharunderscore}SEQ\ L\isactrlisub {\isadigit{1}}\ L\isactrlisub {\isadigit{2}}\ n\ {\isasymLongrightarrow}\ m\ {\isasymapprox}{\isacharparenleft}L\isactrlisub {\isadigit{1}}\ {\isacharsemicolon}{\isacharsemicolon}\ L\isactrlisub {\isadigit{2}}{\isacharparenright}\ n{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp\ add{\isacharcolon}\ str{\isacharunderscore}eq{\isacharunderscore}def\ str{\isacharunderscore}eq{\isacharunderscore}rel{\isacharunderscore}def{\isacharparenright}\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\ \isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ quot{\isacharunderscore}seq{\isacharunderscore}finiteI{\isacharcolon}\isanewline
+\ \ \isakeyword{assumes}\ finite{\isadigit{1}}{\isacharcolon}\ {\isachardoublequoteopen}finite\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isasymapprox}{\isacharparenleft}L\isactrlisub {\isadigit{1}}{\isacharcolon}{\isacharcolon}string\ set{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{and}\ finite{\isadigit{2}}{\isacharcolon}\ {\isachardoublequoteopen}finite\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isasymapprox}L\isactrlisub {\isadigit{2}}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{shows}\ {\isachardoublequoteopen}finite\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isasymapprox}{\isacharparenleft}L\isactrlisub {\isadigit{1}}\ {\isacharsemicolon}{\isacharsemicolon}\ L\isactrlisub {\isadigit{2}}{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+{\isacharparenleft}rule{\isacharunderscore}tac\ f\ {\isacharequal}\ {\isachardoublequoteopen}{\isacharparenleft}op\ {\isacharbackquote}{\isacharparenright}\ {\isacharparenleft}tag{\isacharunderscore}str{\isacharunderscore}SEQ\ L\isactrlisub {\isadigit{1}}\ L\isactrlisub {\isadigit{2}}{\isacharparenright}{\isachardoublequoteclose}\ \isakeyword{in}\ finite{\isacharunderscore}imageD{\isacharparenright}\isanewline
+\ \ \isacommand{show}\isamarkupfalse%
+\ {\isachardoublequoteopen}finite\ {\isacharparenleft}op\ {\isacharbackquote}\ {\isacharparenleft}tag{\isacharunderscore}str{\isacharunderscore}SEQ\ L\isactrlisub {\isadigit{1}}\ L\isactrlisub {\isadigit{2}}{\isacharparenright}\ {\isacharbackquote}\ UNIV\ {\isacharslash}{\isacharslash}\ {\isasymapprox}L\isactrlisub {\isadigit{1}}\ {\isacharsemicolon}{\isacharsemicolon}\ L\isactrlisub {\isadigit{2}}{\isacharparenright}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \isacommand{using}\isamarkupfalse%
+\ finite{\isadigit{1}}\ finite{\isadigit{2}}\isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ intro{\isacharcolon}finite{\isacharunderscore}tag{\isacharunderscore}imageI\ tag{\isacharunderscore}str{\isacharunderscore}seq{\isacharunderscore}range{\isacharunderscore}finite{\isacharparenright}\isanewline
+\isacommand{next}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{show}\isamarkupfalse%
+\ \ {\isachardoublequoteopen}inj{\isacharunderscore}on\ {\isacharparenleft}op\ {\isacharbackquote}\ {\isacharparenleft}tag{\isacharunderscore}str{\isacharunderscore}SEQ\ L\isactrlisub {\isadigit{1}}\ L\isactrlisub {\isadigit{2}}{\isacharparenright}{\isacharparenright}\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isasymapprox}L\isactrlisub {\isadigit{1}}\ {\isacharsemicolon}{\isacharsemicolon}\ L\isactrlisub {\isadigit{2}}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}rule\ tag{\isacharunderscore}image{\isacharunderscore}injI{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}rule\ tag{\isacharunderscore}str{\isacharunderscore}SEQ{\isacharunderscore}injI{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ intro{\isacharcolon}tag{\isacharunderscore}image{\isacharunderscore}injI\ tag{\isacharunderscore}str{\isacharunderscore}SEQ{\isacharunderscore}injI\ simp{\isacharcolon}{\isacharparenright}\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isamarkupsubsection{The case for \isa{ALT}%
+}
+\isamarkuptrue%
+\isacommand{definition}\isamarkupfalse%
+\ \isanewline
+\ \ {\isachardoublequoteopen}tag{\isacharunderscore}str{\isacharunderscore}ALT\ L\isactrlisub {\isadigit{1}}\ L\isactrlisub {\isadigit{2}}\ {\isacharparenleft}x{\isacharcolon}{\isacharcolon}string{\isacharparenright}\ {\isasymequiv}\ {\isacharparenleft}{\isacharparenleft}{\isasymapprox}L\isactrlisub {\isadigit{1}}{\isacharparenright}\ {\isacharbackquote}{\isacharbackquote}\ {\isacharbraceleft}x{\isacharbraceright}{\isacharcomma}\ {\isacharparenleft}{\isasymapprox}L\isactrlisub {\isadigit{2}}{\isacharparenright}\ {\isacharbackquote}{\isacharbackquote}\ {\isacharbraceleft}x{\isacharbraceright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ tag{\isacharunderscore}str{\isacharunderscore}alt{\isacharunderscore}range{\isacharunderscore}finite{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}{\isasymlbrakk}finite\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isasymapprox}L\isactrlisub {\isadigit{1}}{\isacharparenright}{\isacharsemicolon}\ finite\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isasymapprox}L\isactrlisub {\isadigit{2}}{\isacharparenright}{\isasymrbrakk}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ {\isasymLongrightarrow}\ finite\ {\isacharparenleft}range\ {\isacharparenleft}tag{\isacharunderscore}str{\isacharunderscore}ALT\ L\isactrlisub {\isadigit{1}}\ L\isactrlisub {\isadigit{2}}{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}rule{\isacharunderscore}tac\ B\ {\isacharequal}\ {\isachardoublequoteopen}{\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isasymapprox}L\isactrlisub {\isadigit{1}}{\isacharparenright}\ {\isasymtimes}\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isasymapprox}L\isactrlisub {\isadigit{2}}{\isacharparenright}{\isachardoublequoteclose}\ \isakeyword{in}\ finite{\isacharunderscore}subset{\isacharparenright}\isanewline
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}tag{\isacharunderscore}str{\isacharunderscore}ALT{\isacharunderscore}def\ Image{\isacharunderscore}def\ quotient{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ quot{\isacharunderscore}union{\isacharunderscore}finiteI{\isacharcolon}\isanewline
+\ \ \isakeyword{assumes}\ finite{\isadigit{1}}{\isacharcolon}\ {\isachardoublequoteopen}finite\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isasymapprox}{\isacharparenleft}L\isactrlisub {\isadigit{1}}{\isacharcolon}{\isacharcolon}string\ set{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{and}\ finite{\isadigit{2}}{\isacharcolon}\ {\isachardoublequoteopen}finite\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isasymapprox}L\isactrlisub {\isadigit{2}}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{shows}\ {\isachardoublequoteopen}finite\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isasymapprox}{\isacharparenleft}L\isactrlisub {\isadigit{1}}\ {\isasymunion}\ L\isactrlisub {\isadigit{2}}{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+{\isacharparenleft}rule{\isacharunderscore}tac\ f\ {\isacharequal}\ {\isachardoublequoteopen}{\isacharparenleft}op\ {\isacharbackquote}{\isacharparenright}\ {\isacharparenleft}tag{\isacharunderscore}str{\isacharunderscore}ALT\ L\isactrlisub {\isadigit{1}}\ L\isactrlisub {\isadigit{2}}{\isacharparenright}{\isachardoublequoteclose}\ \isakeyword{in}\ finite{\isacharunderscore}imageD{\isacharparenright}\isanewline
+\ \ \isacommand{show}\isamarkupfalse%
+\ {\isachardoublequoteopen}finite\ {\isacharparenleft}op\ {\isacharbackquote}\ {\isacharparenleft}tag{\isacharunderscore}str{\isacharunderscore}ALT\ L\isactrlisub {\isadigit{1}}\ L\isactrlisub {\isadigit{2}}{\isacharparenright}\ {\isacharbackquote}\ UNIV\ {\isacharslash}{\isacharslash}\ {\isasymapprox}L\isactrlisub {\isadigit{1}}\ {\isasymunion}\ L\isactrlisub {\isadigit{2}}{\isacharparenright}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \isacommand{using}\isamarkupfalse%
+\ finite{\isadigit{1}}\ finite{\isadigit{2}}\isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ intro{\isacharcolon}finite{\isacharunderscore}tag{\isacharunderscore}imageI\ tag{\isacharunderscore}str{\isacharunderscore}alt{\isacharunderscore}range{\isacharunderscore}finite{\isacharparenright}\isanewline
+\isacommand{next}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{show}\isamarkupfalse%
+\ {\isachardoublequoteopen}inj{\isacharunderscore}on\ {\isacharparenleft}op\ {\isacharbackquote}\ {\isacharparenleft}tag{\isacharunderscore}str{\isacharunderscore}ALT\ L\isactrlisub {\isadigit{1}}\ L\isactrlisub {\isadigit{2}}{\isacharparenright}{\isacharparenright}\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isasymapprox}L\isactrlisub {\isadigit{1}}\ {\isasymunion}\ L\isactrlisub {\isadigit{2}}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \isacommand{proof}\isamarkupfalse%
+{\isacharminus}\isanewline
+\ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isasymAnd}m\ n{\isachardot}\ tag{\isacharunderscore}str{\isacharunderscore}ALT\ L\isactrlisub {\isadigit{1}}\ L\isactrlisub {\isadigit{2}}\ m\ {\isacharequal}\ tag{\isacharunderscore}str{\isacharunderscore}ALT\ L\isactrlisub {\isadigit{1}}\ L\isactrlisub {\isadigit{2}}\ n\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ {\isasymLongrightarrow}\ m\ {\isasymapprox}{\isacharparenleft}L\isactrlisub {\isadigit{1}}\ {\isasymunion}\ L\isactrlisub {\isadigit{2}}{\isacharparenright}\ n{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \isacommand{unfolding}\isamarkupfalse%
+\ tag{\isacharunderscore}str{\isacharunderscore}ALT{\isacharunderscore}def\ str{\isacharunderscore}eq{\isacharunderscore}def\ Image{\isacharunderscore}def\ str{\isacharunderscore}eq{\isacharunderscore}rel{\isacharunderscore}def\ \isacommand{by}\isamarkupfalse%
+\ auto\isanewline
+\ \ \ \ \isacommand{thus}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ intro{\isacharcolon}tag{\isacharunderscore}image{\isacharunderscore}injI{\isacharparenright}\isanewline
+\ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isamarkupsubsection{The case for \isa{STAR}%
+}
+\isamarkuptrue%
+%
+\begin{isamarkuptext}%
+This turned out to be the most tricky case.%
+\end{isamarkuptext}%
+\isamarkuptrue%
+\isacommand{definition}\isamarkupfalse%
+\ \isanewline
+\ \ {\isachardoublequoteopen}tag{\isacharunderscore}str{\isacharunderscore}STAR\ L\isactrlisub {\isadigit{1}}\ x\ {\isasymequiv}\ {\isacharbraceleft}{\isacharparenleft}{\isasymapprox}L\isactrlisub {\isadigit{1}}{\isacharparenright}\ {\isacharbackquote}{\isacharbackquote}\ {\isacharbraceleft}x\ {\isacharminus}\ xa{\isacharbraceright}\ {\isacharbar}\ xa{\isachardot}\ xa\ {\isacharless}\ x\ {\isasymand}\ xa\ {\isasymin}\ L\isactrlisub {\isadigit{1}}{\isasymstar}{\isacharbraceright}{\isachardoublequoteclose}\isanewline
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ finite{\isacharunderscore}set{\isacharunderscore}has{\isacharunderscore}max{\isacharcolon}\ {\isachardoublequoteopen}{\isasymlbrakk}finite\ A{\isacharsemicolon}\ A\ {\isasymnoteq}\ {\isacharbraceleft}{\isacharbraceright}{\isasymrbrakk}\ {\isasymLongrightarrow}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ {\isacharparenleft}{\isasymexists}\ max\ {\isasymin}\ A{\isachardot}\ {\isasymforall}\ a\ {\isasymin}\ A{\isachardot}\ f\ a\ {\isacharless}{\isacharequal}\ {\isacharparenleft}f\ max\ {\isacharcolon}{\isacharcolon}\ nat{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+\ {\isacharparenleft}induct\ rule{\isacharcolon}finite{\isachardot}induct{\isacharparenright}\isanewline
+\ \ \isacommand{case}\isamarkupfalse%
+\ emptyI\ \isacommand{thus}\isamarkupfalse%
+\ {\isacharquery}case\ \isacommand{by}\isamarkupfalse%
+\ simp\isanewline
+\isacommand{next}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{case}\isamarkupfalse%
+\ {\isacharparenleft}insertI\ A\ a{\isacharparenright}\isanewline
+\ \ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}case\isanewline
+\ \ \isacommand{proof}\isamarkupfalse%
+\ {\isacharparenleft}cases\ {\isachardoublequoteopen}A\ {\isacharequal}\ {\isacharbraceleft}{\isacharbraceright}{\isachardoublequoteclose}{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{case}\isamarkupfalse%
+\ True\ \isacommand{thus}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}rule{\isacharunderscore}tac\ x\ {\isacharequal}\ a\ \isakeyword{in}\ bexI{\isacharcomma}\ auto{\isacharparenright}\isanewline
+\ \ \isacommand{next}\isamarkupfalse%
+\isanewline
+\ \ \ \ \isacommand{case}\isamarkupfalse%
+\ False\isanewline
+\ \ \ \ \isacommand{with}\isamarkupfalse%
+\ prems\ \isacommand{obtain}\isamarkupfalse%
+\ max\ \isanewline
+\ \ \ \ \ \ \isakeyword{where}\ h{\isadigit{1}}{\isacharcolon}\ {\isachardoublequoteopen}max\ {\isasymin}\ A{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \ \ \isakeyword{and}\ h{\isadigit{2}}{\isacharcolon}\ {\isachardoublequoteopen}{\isasymforall}a{\isasymin}A{\isachardot}\ f\ a\ {\isasymle}\ f\ max{\isachardoublequoteclose}\ \isacommand{by}\isamarkupfalse%
+\ blast\isanewline
+\ \ \ \ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\isanewline
+\ \ \ \ \isacommand{proof}\isamarkupfalse%
+\ {\isacharparenleft}cases\ {\isachardoublequoteopen}f\ a\ {\isasymle}\ f\ max{\isachardoublequoteclose}{\isacharparenright}\isanewline
+\ \ \ \ \ \ \isacommand{assume}\isamarkupfalse%
+\ {\isachardoublequoteopen}f\ a\ {\isasymle}\ f\ max{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \isacommand{with}\isamarkupfalse%
+\ h{\isadigit{1}}\ h{\isadigit{2}}\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}rule{\isacharunderscore}tac\ x\ {\isacharequal}\ max\ \isakeyword{in}\ bexI{\isacharcomma}\ auto{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{next}\isamarkupfalse%
+\isanewline
+\ \ \ \ \ \ \isacommand{assume}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isasymnot}\ {\isacharparenleft}f\ a\ {\isasymle}\ f\ max{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \isacommand{thus}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{using}\isamarkupfalse%
+\ h{\isadigit{2}}\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}rule{\isacharunderscore}tac\ x\ {\isacharequal}\ a\ \isakeyword{in}\ bexI{\isacharcomma}\ auto{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ finite{\isacharunderscore}strict{\isacharunderscore}prefix{\isacharunderscore}set{\isacharcolon}\ {\isachardoublequoteopen}finite\ {\isacharbraceleft}xa{\isachardot}\ xa\ {\isacharless}\ {\isacharparenleft}x{\isacharcolon}{\isacharcolon}string{\isacharparenright}{\isacharbraceright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}induct\ x\ rule{\isacharcolon}rev{\isacharunderscore}induct{\isacharcomma}\ simp{\isacharparenright}\isanewline
+\isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}subgoal{\isacharunderscore}tac\ {\isachardoublequoteopen}{\isacharbraceleft}xa{\isachardot}\ xa\ {\isacharless}\ xs\ {\isacharat}\ {\isacharbrackleft}x{\isacharbrackright}{\isacharbraceright}\ {\isacharequal}\ {\isacharbraceleft}xa{\isachardot}\ xa\ {\isacharless}\ xs{\isacharbraceright}\ {\isasymunion}\ {\isacharbraceleft}xs{\isacharbraceright}{\isachardoublequoteclose}{\isacharparenright}\isanewline
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}strict{\isacharunderscore}prefix{\isacharunderscore}def{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ tag{\isacharunderscore}str{\isacharunderscore}star{\isacharunderscore}range{\isacharunderscore}finite{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}finite\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isasymapprox}L\isactrlisub {\isadigit{1}}{\isacharparenright}\ {\isasymLongrightarrow}\ finite\ {\isacharparenleft}range\ {\isacharparenleft}tag{\isacharunderscore}str{\isacharunderscore}STAR\ L\isactrlisub {\isadigit{1}}{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{apply}\isamarkupfalse%
+\ {\isacharparenleft}rule{\isacharunderscore}tac\ B\ {\isacharequal}\ {\isachardoublequoteopen}Pow\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isasymapprox}L\isactrlisub {\isadigit{1}}{\isacharparenright}{\isachardoublequoteclose}\ \isakeyword{in}\ finite{\isacharunderscore}subset{\isacharparenright}\isanewline
+\isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}tag{\isacharunderscore}str{\isacharunderscore}STAR{\isacharunderscore}def\ Image{\isacharunderscore}def\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ quotient{\isacharunderscore}def\ split{\isacharcolon}if{\isacharunderscore}splits{\isacharparenright}%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ tag{\isacharunderscore}str{\isacharunderscore}STAR{\isacharunderscore}injI{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}tag{\isacharunderscore}str{\isacharunderscore}STAR\ L\isactrlisub {\isadigit{1}}\ m\ {\isacharequal}\ tag{\isacharunderscore}str{\isacharunderscore}STAR\ L\isactrlisub {\isadigit{1}}\ n\ {\isasymLongrightarrow}\ m\ {\isasymapprox}{\isacharparenleft}L\isactrlisub {\isadigit{1}}{\isasymstar}{\isacharparenright}\ n{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+{\isacharminus}\isanewline
+\ \ \isacommand{{\isacharbraceleft}}\isamarkupfalse%
+\ \isacommand{fix}\isamarkupfalse%
+\ x\ y\ z\isanewline
+\ \ \ \ \isacommand{assume}\isamarkupfalse%
+\ xz{\isacharunderscore}in{\isacharunderscore}star{\isacharcolon}\ {\isachardoublequoteopen}x\ {\isacharat}\ z\ {\isasymin}\ L\isactrlisub {\isadigit{1}}{\isasymstar}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isakeyword{and}\ tag{\isacharunderscore}xy{\isacharcolon}\ {\isachardoublequoteopen}tag{\isacharunderscore}str{\isacharunderscore}STAR\ L\isactrlisub {\isadigit{1}}\ x\ {\isacharequal}\ tag{\isacharunderscore}str{\isacharunderscore}STAR\ L\isactrlisub {\isadigit{1}}\ y{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}y\ {\isacharat}\ z\ {\isasymin}\ L\isactrlisub {\isadigit{1}}{\isasymstar}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{proof}\isamarkupfalse%
+{\isacharparenleft}cases\ {\isachardoublequoteopen}x\ {\isacharequal}\ {\isacharbrackleft}{\isacharbrackright}{\isachardoublequoteclose}{\isacharparenright}\isanewline
+\ \ \ \ \ \ \isacommand{case}\isamarkupfalse%
+\ True\isanewline
+\ \ \ \ \ \ \isacommand{with}\isamarkupfalse%
+\ tag{\isacharunderscore}xy\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}y\ {\isacharequal}\ {\isacharbrackleft}{\isacharbrackright}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}tag{\isacharunderscore}str{\isacharunderscore}STAR{\isacharunderscore}def\ strict{\isacharunderscore}prefix{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \ \ \ \ \isacommand{thus}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{using}\isamarkupfalse%
+\ xz{\isacharunderscore}in{\isacharunderscore}star\ True\ \isacommand{by}\isamarkupfalse%
+\ simp\isanewline
+\ \ \ \ \isacommand{next}\isamarkupfalse%
+\isanewline
+\ \ \ \ \ \ \isacommand{case}\isamarkupfalse%
+\ False\isanewline
+\ \ \ \ \ \ \isacommand{obtain}\isamarkupfalse%
+\ x{\isacharunderscore}max\ \isanewline
+\ \ \ \ \ \ \ \ \isakeyword{where}\ h{\isadigit{1}}{\isacharcolon}\ {\isachardoublequoteopen}x{\isacharunderscore}max\ {\isacharless}\ x{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \ \ \ \ \isakeyword{and}\ h{\isadigit{2}}{\isacharcolon}\ {\isachardoublequoteopen}x{\isacharunderscore}max\ {\isasymin}\ L\isactrlisub {\isadigit{1}}{\isasymstar}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \ \ \ \ \isakeyword{and}\ h{\isadigit{3}}{\isacharcolon}\ {\isachardoublequoteopen}{\isacharparenleft}x\ {\isacharminus}\ x{\isacharunderscore}max{\isacharparenright}\ {\isacharat}\ z\ {\isasymin}\ L\isactrlisub {\isadigit{1}}{\isasymstar}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \ \ \ \ \isakeyword{and}\ h{\isadigit{4}}{\isacharcolon}{\isachardoublequoteopen}{\isasymforall}\ xa\ {\isacharless}\ x{\isachardot}\ xa\ {\isasymin}\ L\isactrlisub {\isadigit{1}}{\isasymstar}\ {\isasymand}\ {\isacharparenleft}x\ {\isacharminus}\ xa{\isacharparenright}\ {\isacharat}\ z\ {\isasymin}\ L\isactrlisub {\isadigit{1}}{\isasymstar}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ {\isasymlongrightarrow}\ length\ xa\ {\isasymle}\ length\ x{\isacharunderscore}max{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \isacommand{proof}\isamarkupfalse%
+{\isacharminus}\isanewline
+\ \ \ \ \ \ \ \ \isacommand{let}\isamarkupfalse%
+\ {\isacharquery}S\ {\isacharequal}\ {\isachardoublequoteopen}{\isacharbraceleft}xa{\isachardot}\ xa\ {\isacharless}\ x\ {\isasymand}\ xa\ {\isasymin}\ L\isactrlisub {\isadigit{1}}{\isasymstar}\ {\isasymand}\ {\isacharparenleft}x\ {\isacharminus}\ xa{\isacharparenright}\ {\isacharat}\ z\ {\isasymin}\ L\isactrlisub {\isadigit{1}}{\isasymstar}{\isacharbraceright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}finite\ {\isacharquery}S{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}rule{\isacharunderscore}tac\ B\ {\isacharequal}\ {\isachardoublequoteopen}{\isacharbraceleft}xa{\isachardot}\ xa\ {\isacharless}\ x{\isacharbraceright}{\isachardoublequoteclose}\ \isakeyword{in}\ finite{\isacharunderscore}subset{\isacharcomma}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ auto\ simp{\isacharcolon}finite{\isacharunderscore}strict{\isacharunderscore}prefix{\isacharunderscore}set{\isacharparenright}\isanewline
+\ \ \ \ \ \ \ \ \isacommand{moreover}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isacharquery}S\ {\isasymnoteq}\ {\isacharbraceleft}{\isacharbraceright}{\isachardoublequoteclose}\ \isacommand{using}\isamarkupfalse%
+\ False\ xz{\isacharunderscore}in{\isacharunderscore}star\isanewline
+\ \ \ \ \ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}simp{\isacharcomma}\ rule{\isacharunderscore}tac\ x\ {\isacharequal}\ {\isachardoublequoteopen}{\isacharbrackleft}{\isacharbrackright}{\isachardoublequoteclose}\ \isakeyword{in}\ exI{\isacharcomma}\ auto\ simp{\isacharcolon}strict{\isacharunderscore}prefix{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \ \ \ \ \ \ \isacommand{ultimately}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isasymexists}\ max\ {\isasymin}\ {\isacharquery}S{\isachardot}\ {\isasymforall}\ a\ {\isasymin}\ {\isacharquery}S{\isachardot}\ length\ a\ {\isasymle}\ length\ max{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \isacommand{using}\isamarkupfalse%
+\ finite{\isacharunderscore}set{\isacharunderscore}has{\isacharunderscore}max\ \isacommand{by}\isamarkupfalse%
+\ blast\isanewline
+\ \ \ \ \ \ \ \ \isacommand{with}\isamarkupfalse%
+\ prems\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ blast\isanewline
+\ \ \ \ \ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\ \ \ \ \ \ \isacommand{obtain}\isamarkupfalse%
+\ ya\ \isanewline
+\ \ \ \ \ \ \ \ \isakeyword{where}\ h{\isadigit{5}}{\isacharcolon}\ {\isachardoublequoteopen}ya\ {\isacharless}\ y{\isachardoublequoteclose}\ \isakeyword{and}\ h{\isadigit{6}}{\isacharcolon}\ {\isachardoublequoteopen}ya\ {\isasymin}\ L\isactrlisub {\isadigit{1}}{\isasymstar}{\isachardoublequoteclose}\ \isakeyword{and}\ h{\isadigit{7}}{\isacharcolon}\ {\isachardoublequoteopen}{\isacharparenleft}x\ {\isacharminus}\ x{\isacharunderscore}max{\isacharparenright}\ {\isasymapprox}L\isactrlisub {\isadigit{1}}\ {\isacharparenleft}y\ {\isacharminus}\ ya{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \isacommand{proof}\isamarkupfalse%
+{\isacharminus}\isanewline
+\ \ \ \ \ \ \ \ \isacommand{from}\isamarkupfalse%
+\ tag{\isacharunderscore}xy\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isacharbraceleft}{\isasymapprox}L\isactrlisub {\isadigit{1}}\ {\isacharbackquote}{\isacharbackquote}\ {\isacharbraceleft}x\ {\isacharminus}\ xa{\isacharbraceright}\ {\isacharbar}xa{\isachardot}\ xa\ {\isacharless}\ x\ {\isasymand}\ xa\ {\isasymin}\ L\isactrlisub {\isadigit{1}}{\isasymstar}{\isacharbraceright}\ {\isacharequal}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ {\isacharbraceleft}{\isasymapprox}L\isactrlisub {\isadigit{1}}\ {\isacharbackquote}{\isacharbackquote}\ {\isacharbraceleft}y\ {\isacharminus}\ xa{\isacharbraceright}\ {\isacharbar}xa{\isachardot}\ xa\ {\isacharless}\ y\ {\isasymand}\ xa\ {\isasymin}\ L\isactrlisub {\isadigit{1}}{\isasymstar}{\isacharbraceright}{\isachardoublequoteclose}\ {\isacharparenleft}\isakeyword{is}\ {\isachardoublequoteopen}{\isacharquery}left\ {\isacharequal}\ {\isacharquery}right{\isachardoublequoteclose}{\isacharparenright}\isanewline
+\ \ \ \ \ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}tag{\isacharunderscore}str{\isacharunderscore}STAR{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \ \ \ \ \ \ \isacommand{moreover}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isasymapprox}L\isactrlisub {\isadigit{1}}\ {\isacharbackquote}{\isacharbackquote}\ {\isacharbraceleft}x\ {\isacharminus}\ x{\isacharunderscore}max{\isacharbraceright}\ {\isasymin}\ {\isacharquery}left{\isachardoublequoteclose}\ \isacommand{using}\isamarkupfalse%
+\ h{\isadigit{1}}\ h{\isadigit{2}}\ \isacommand{by}\isamarkupfalse%
+\ auto\isanewline
+\ \ \ \ \ \ \ \ \isacommand{ultimately}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isasymapprox}L\isactrlisub {\isadigit{1}}\ {\isacharbackquote}{\isacharbackquote}\ {\isacharbraceleft}x\ {\isacharminus}\ x{\isacharunderscore}max{\isacharbraceright}\ {\isasymin}\ {\isacharquery}right{\isachardoublequoteclose}\ \isacommand{by}\isamarkupfalse%
+\ simp\isanewline
+\ \ \ \ \ \ \ \ \isacommand{with}\isamarkupfalse%
+\ prems\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{apply}\isamarkupfalse%
+\ \isanewline
+\ \ \ \ \ \ \ \ \ \ {\isacharparenleft}simp\ add{\isacharcolon}Image{\isacharunderscore}def\ str{\isacharunderscore}eq{\isacharunderscore}rel{\isacharunderscore}def\ str{\isacharunderscore}eq{\isacharunderscore}def{\isacharparenright}\ \isacommand{by}\isamarkupfalse%
+\ blast\isanewline
+\ \ \ \ \ \ \isacommand{qed}\isamarkupfalse%
+\ \ \ \ \ \ \isanewline
+\ \ \ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isacharparenleft}y\ {\isacharminus}\ ya{\isacharparenright}\ {\isacharat}\ z\ {\isasymin}\ L\isactrlisub {\isadigit{1}}{\isasymstar}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \ \ \isacommand{proof}\isamarkupfalse%
+{\isacharminus}\isanewline
+\ \ \ \ \ \ \ \ \isacommand{from}\isamarkupfalse%
+\ h{\isadigit{3}}\ h{\isadigit{1}}\ \isacommand{obtain}\isamarkupfalse%
+\ a\ b\ \isakeyword{where}\ a{\isacharunderscore}in{\isacharcolon}\ {\isachardoublequoteopen}a\ {\isasymin}\ L\isactrlisub {\isadigit{1}}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \isakeyword{and}\ a{\isacharunderscore}neq{\isacharcolon}\ {\isachardoublequoteopen}a\ {\isasymnoteq}\ {\isacharbrackleft}{\isacharbrackright}{\isachardoublequoteclose}\ \isakeyword{and}\ b{\isacharunderscore}in{\isacharcolon}\ {\isachardoublequoteopen}b\ {\isasymin}\ L\isactrlisub {\isadigit{1}}{\isasymstar}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \isakeyword{and}\ ab{\isacharunderscore}max{\isacharcolon}\ {\isachardoublequoteopen}{\isacharparenleft}x\ {\isacharminus}\ x{\isacharunderscore}max{\isacharparenright}\ {\isacharat}\ z\ {\isacharequal}\ a\ {\isacharat}\ b{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}drule{\isacharunderscore}tac\ star{\isacharunderscore}decom{\isacharcomma}\ auto\ simp{\isacharcolon}strict{\isacharunderscore}prefix{\isacharunderscore}def\ elim{\isacharcolon}prefixE{\isacharparenright}\isanewline
+\ \ \ \ \ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isacharparenleft}x\ {\isacharminus}\ x{\isacharunderscore}max{\isacharparenright}\ {\isasymle}\ a\ {\isasymand}\ {\isacharparenleft}a\ {\isacharminus}\ {\isacharparenleft}x\ {\isacharminus}\ x{\isacharunderscore}max{\isacharparenright}{\isacharparenright}\ {\isacharat}\ b\ {\isacharequal}\ z{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \ \ \ \ \isacommand{proof}\isamarkupfalse%
+\ {\isacharminus}\isanewline
+\ \ \ \ \ \ \ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isacharparenleft}{\isacharparenleft}x\ {\isacharminus}\ x{\isacharunderscore}max{\isacharparenright}\ {\isasymle}\ a\ {\isasymand}\ {\isacharparenleft}a\ {\isacharminus}\ {\isacharparenleft}x\ {\isacharminus}\ x{\isacharunderscore}max{\isacharparenright}{\isacharparenright}\ {\isacharat}\ b\ {\isacharequal}\ z{\isacharparenright}\ {\isasymor}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ {\isacharparenleft}a\ {\isacharless}\ {\isacharparenleft}x\ {\isacharminus}\ x{\isacharunderscore}max{\isacharparenright}\ {\isasymand}\ {\isacharparenleft}{\isacharparenleft}x\ {\isacharminus}\ x{\isacharunderscore}max{\isacharparenright}\ {\isacharminus}\ a{\isacharparenright}\ {\isacharat}\ z\ {\isacharequal}\ b{\isacharparenright}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \isacommand{using}\isamarkupfalse%
+\ app{\isacharunderscore}eq{\isacharunderscore}dest{\isacharbrackleft}OF\ ab{\isacharunderscore}max{\isacharbrackright}\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}strict{\isacharunderscore}prefix{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \ \ \ \ \ \ \ \ \isacommand{moreover}\isamarkupfalse%
+\ \isacommand{{\isacharbraceleft}}\isamarkupfalse%
+\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \isacommand{assume}\isamarkupfalse%
+\ np{\isacharcolon}\ {\isachardoublequoteopen}a\ {\isacharless}\ {\isacharparenleft}x\ {\isacharminus}\ x{\isacharunderscore}max{\isacharparenright}{\isachardoublequoteclose}\ \isakeyword{and}\ b{\isacharunderscore}eqs{\isacharcolon}\ {\isachardoublequoteopen}\ {\isacharparenleft}{\isacharparenleft}x\ {\isacharminus}\ x{\isacharunderscore}max{\isacharparenright}\ {\isacharminus}\ a{\isacharparenright}\ {\isacharat}\ z\ {\isacharequal}\ b{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}False{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \isacommand{proof}\isamarkupfalse%
+\ {\isacharminus}\isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \isacommand{let}\isamarkupfalse%
+\ {\isacharquery}x{\isacharunderscore}max{\isacharprime}\ {\isacharequal}\ {\isachardoublequoteopen}x{\isacharunderscore}max\ {\isacharat}\ a{\isachardoublequoteclose}\isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isacharquery}x{\isacharunderscore}max{\isacharprime}\ {\isacharless}\ x{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \isacommand{using}\isamarkupfalse%
+\ np\ h{\isadigit{1}}\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}clarsimp\ simp{\isacharcolon}strict{\isacharunderscore}prefix{\isacharunderscore}def\ diff{\isacharunderscore}prefix{\isacharparenright}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \isacommand{moreover}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isacharquery}x{\isacharunderscore}max{\isacharprime}\ {\isasymin}\ L\isactrlisub {\isadigit{1}}{\isasymstar}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \isacommand{using}\isamarkupfalse%
+\ a{\isacharunderscore}in\ h{\isadigit{2}}\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}simp\ add{\isacharcolon}star{\isacharunderscore}intro{\isadigit{3}}{\isacharparenright}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \isacommand{moreover}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isacharparenleft}x\ {\isacharminus}\ {\isacharquery}x{\isacharunderscore}max{\isacharprime}{\isacharparenright}\ {\isacharat}\ z\ {\isasymin}\ L\isactrlisub {\isadigit{1}}{\isasymstar}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \isacommand{using}\isamarkupfalse%
+\ b{\isacharunderscore}eqs\ b{\isacharunderscore}in\ np\ h{\isadigit{1}}\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}simp\ add{\isacharcolon}diff{\isacharunderscore}diff{\isacharunderscore}appd{\isacharparenright}\isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \isacommand{moreover}\isamarkupfalse%
+\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isasymnot}\ {\isacharparenleft}length\ {\isacharquery}x{\isacharunderscore}max{\isacharprime}\ {\isasymle}\ length\ x{\isacharunderscore}max{\isacharparenright}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \isacommand{using}\isamarkupfalse%
+\ a{\isacharunderscore}neq\ \isacommand{by}\isamarkupfalse%
+\ simp\isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \isacommand{ultimately}\isamarkupfalse%
+\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{using}\isamarkupfalse%
+\ h{\isadigit{4}}\ \isacommand{by}\isamarkupfalse%
+\ blast\isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ \isacommand{qed}\isamarkupfalse%
+\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \isacommand{{\isacharbraceright}}\isamarkupfalse%
+\ \isacommand{ultimately}\isamarkupfalse%
+\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ blast\isanewline
+\ \ \ \ \ \ \ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\ \ \ \ \ \ \ \ \isacommand{then}\isamarkupfalse%
+\ \isacommand{obtain}\isamarkupfalse%
+\ za\ \isakeyword{where}\ z{\isacharunderscore}decom{\isacharcolon}\ {\isachardoublequoteopen}z\ {\isacharequal}\ za\ {\isacharat}\ b{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \isakeyword{and}\ x{\isacharunderscore}za{\isacharcolon}\ {\isachardoublequoteopen}{\isacharparenleft}x\ {\isacharminus}\ x{\isacharunderscore}max{\isacharparenright}\ {\isacharat}\ za\ {\isasymin}\ L\isactrlisub {\isadigit{1}}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \isacommand{using}\isamarkupfalse%
+\ a{\isacharunderscore}in\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ elim{\isacharcolon}prefixE{\isacharparenright}\ \ \ \ \ \ \ \ \isanewline
+\ \ \ \ \ \ \ \ \isacommand{from}\isamarkupfalse%
+\ x{\isacharunderscore}za\ h{\isadigit{7}}\ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isacharparenleft}y\ {\isacharminus}\ ya{\isacharparenright}\ {\isacharat}\ za\ {\isasymin}\ L\isactrlisub {\isadigit{1}}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}str{\isacharunderscore}eq{\isacharunderscore}def\ str{\isacharunderscore}eq{\isacharunderscore}rel{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \ \ \ \ \ \ \isacommand{with}\isamarkupfalse%
+\ z{\isacharunderscore}decom\ b{\isacharunderscore}in\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ dest{\isacharbang}{\isacharcolon}step{\isacharbrackleft}of\ {\isachardoublequoteopen}{\isacharparenleft}y\ {\isacharminus}\ ya{\isacharparenright}\ {\isacharat}\ za{\isachardoublequoteclose}{\isacharbrackright}{\isacharparenright}\isanewline
+\ \ \ \ \ \ \isacommand{qed}\isamarkupfalse%
+\isanewline
+\ \ \ \ \ \ \isacommand{with}\isamarkupfalse%
+\ h{\isadigit{5}}\ h{\isadigit{6}}\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}thesis\ \isanewline
+\ \ \ \ \ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}drule{\isacharunderscore}tac\ star{\isacharunderscore}intro{\isadigit{1}}{\isacharcomma}\ auto\ simp{\isacharcolon}strict{\isacharunderscore}prefix{\isacharunderscore}def\ elim{\isacharcolon}prefixE{\isacharparenright}\isanewline
+\ \ \ \ \isacommand{qed}\isamarkupfalse%
+\ \ \ \ \ \ \isanewline
+\ \ \isacommand{{\isacharbraceright}}\isamarkupfalse%
+\ \isacommand{thus}\isamarkupfalse%
+\ {\isachardoublequoteopen}tag{\isacharunderscore}str{\isacharunderscore}STAR\ L\isactrlisub {\isadigit{1}}\ m\ {\isacharequal}\ tag{\isacharunderscore}str{\isacharunderscore}STAR\ L\isactrlisub {\isadigit{1}}\ n\ {\isasymLongrightarrow}\ m\ {\isasymapprox}{\isacharparenleft}L\isactrlisub {\isadigit{1}}{\isasymstar}{\isacharparenright}\ n{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp\ add{\isacharcolon}str{\isacharunderscore}eq{\isacharunderscore}def\ str{\isacharunderscore}eq{\isacharunderscore}rel{\isacharunderscore}def{\isacharparenright}\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\isanewline
+%
+\endisadelimproof
+\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ quot{\isacharunderscore}star{\isacharunderscore}finiteI{\isacharcolon}\isanewline
+\ \ \isakeyword{assumes}\ finite{\isacharcolon}\ {\isachardoublequoteopen}finite\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isasymapprox}{\isacharparenleft}L\isactrlisub {\isadigit{1}}{\isacharcolon}{\isacharcolon}string\ set{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \isakeyword{shows}\ {\isachardoublequoteopen}finite\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isasymapprox}{\isacharparenleft}L\isactrlisub {\isadigit{1}}{\isasymstar}{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+{\isacharparenleft}rule{\isacharunderscore}tac\ f\ {\isacharequal}\ {\isachardoublequoteopen}{\isacharparenleft}op\ {\isacharbackquote}{\isacharparenright}\ {\isacharparenleft}tag{\isacharunderscore}str{\isacharunderscore}STAR\ L\isactrlisub {\isadigit{1}}{\isacharparenright}{\isachardoublequoteclose}\ \isakeyword{in}\ finite{\isacharunderscore}imageD{\isacharparenright}\isanewline
+\ \ \isacommand{show}\isamarkupfalse%
+\ {\isachardoublequoteopen}finite\ {\isacharparenleft}op\ {\isacharbackquote}\ {\isacharparenleft}tag{\isacharunderscore}str{\isacharunderscore}STAR\ L\isactrlisub {\isadigit{1}}{\isacharparenright}\ {\isacharbackquote}\ UNIV\ {\isacharslash}{\isacharslash}\ {\isasymapprox}L\isactrlisub {\isadigit{1}}{\isasymstar}{\isacharparenright}{\isachardoublequoteclose}\ \isacommand{using}\isamarkupfalse%
+\ finite\isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ intro{\isacharcolon}finite{\isacharunderscore}tag{\isacharunderscore}imageI\ tag{\isacharunderscore}str{\isacharunderscore}star{\isacharunderscore}range{\isacharunderscore}finite{\isacharparenright}\isanewline
+\isacommand{next}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{show}\isamarkupfalse%
+\ {\isachardoublequoteopen}inj{\isacharunderscore}on\ {\isacharparenleft}op\ {\isacharbackquote}\ {\isacharparenleft}tag{\isacharunderscore}str{\isacharunderscore}STAR\ L\isactrlisub {\isadigit{1}}{\isacharparenright}{\isacharparenright}\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isasymapprox}L\isactrlisub {\isadigit{1}}{\isasymstar}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ intro{\isacharcolon}tag{\isacharunderscore}image{\isacharunderscore}injI\ tag{\isacharunderscore}str{\isacharunderscore}STAR{\isacharunderscore}injI{\isacharparenright}\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isamarkupsubsection{The main lemma%
+}
+\isamarkuptrue%
+\isacommand{lemma}\isamarkupfalse%
+\ easier{\isacharunderscore}directio{\isasymnu}{\isacharcolon}\isanewline
+\ \ {\isachardoublequoteopen}Lang\ {\isacharequal}\ L\ {\isacharparenleft}r{\isacharcolon}{\isacharcolon}rexp{\isacharparenright}\ {\isasymLongrightarrow}\ finite\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isacharparenleft}{\isasymapprox}Lang{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+%
+\isadelimproof
+%
+\endisadelimproof
+%
+\isatagproof
+\isacommand{proof}\isamarkupfalse%
+\ {\isacharparenleft}induct\ arbitrary{\isacharcolon}Lang\ rule{\isacharcolon}rexp{\isachardot}induct{\isacharparenright}\isanewline
+\ \ \isacommand{case}\isamarkupfalse%
+\ NULL\isanewline
+\ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}UNIV\ {\isacharslash}{\isacharslash}\ {\isacharparenleft}{\isasymapprox}{\isacharbraceleft}{\isacharbraceright}{\isacharparenright}\ {\isasymsubseteq}\ {\isacharbraceleft}UNIV{\isacharbraceright}\ {\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ simp{\isacharcolon}quotient{\isacharunderscore}def\ str{\isacharunderscore}eq{\isacharunderscore}rel{\isacharunderscore}def\ str{\isacharunderscore}eq{\isacharunderscore}def{\isacharparenright}\isanewline
+\ \ \isacommand{with}\isamarkupfalse%
+\ prems\ \isacommand{show}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isacharquery}case{\isachardoublequoteclose}\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ intro{\isacharcolon}finite{\isacharunderscore}subset{\isacharparenright}\isanewline
+\isacommand{next}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{case}\isamarkupfalse%
+\ EMPTY\isanewline
+\ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}UNIV\ {\isacharslash}{\isacharslash}\ {\isacharparenleft}{\isasymapprox}{\isacharbraceleft}{\isacharbrackleft}{\isacharbrackright}{\isacharbraceright}{\isacharparenright}\ {\isasymsubseteq}\ {\isacharbraceleft}{\isacharbraceleft}{\isacharbrackleft}{\isacharbrackright}{\isacharbraceright}{\isacharcomma}\ UNIV\ {\isacharminus}\ {\isacharbraceleft}{\isacharbrackleft}{\isacharbrackright}{\isacharbraceright}{\isacharbraceright}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}rule\ quot{\isacharunderscore}empty{\isacharunderscore}subset{\isacharparenright}\isanewline
+\ \ \isacommand{with}\isamarkupfalse%
+\ prems\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}case\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ intro{\isacharcolon}finite{\isacharunderscore}subset{\isacharparenright}\isanewline
+\isacommand{next}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{case}\isamarkupfalse%
+\ {\isacharparenleft}CHAR\ c{\isacharparenright}\isanewline
+\ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}UNIV\ {\isacharslash}{\isacharslash}\ {\isacharparenleft}{\isasymapprox}{\isacharbraceleft}{\isacharbrackleft}c{\isacharbrackright}{\isacharbraceright}{\isacharparenright}\ {\isasymsubseteq}\ {\isacharbraceleft}{\isacharbraceleft}{\isacharbrackleft}{\isacharbrackright}{\isacharbraceright}{\isacharcomma}{\isacharbraceleft}{\isacharbrackleft}c{\isacharbrackright}{\isacharbraceright}{\isacharcomma}\ UNIV\ {\isacharminus}\ {\isacharbraceleft}{\isacharbrackleft}{\isacharbrackright}{\isacharcomma}\ {\isacharbrackleft}c{\isacharbrackright}{\isacharbraceright}{\isacharbraceright}{\isachardoublequoteclose}\ \isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}rule\ quot{\isacharunderscore}char{\isacharunderscore}subset{\isacharparenright}\isanewline
+\ \ \isacommand{with}\isamarkupfalse%
+\ prems\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}case\ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}auto\ intro{\isacharcolon}finite{\isacharunderscore}subset{\isacharparenright}\isanewline
+\isacommand{next}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{case}\isamarkupfalse%
+\ {\isacharparenleft}SEQ\ r\isactrlisub {\isadigit{1}}\ r\isactrlisub {\isadigit{2}}{\isacharparenright}\isanewline
+\ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isasymlbrakk}finite\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isasymapprox}{\isacharparenleft}L\ r\isactrlisub {\isadigit{1}}{\isacharparenright}{\isacharparenright}{\isacharsemicolon}\ finite\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isasymapprox}{\isacharparenleft}L\ r\isactrlisub {\isadigit{2}}{\isacharparenright}{\isacharparenright}{\isasymrbrakk}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ {\isasymLongrightarrow}\ finite\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isasymapprox}{\isacharparenleft}L\ r\isactrlisub {\isadigit{1}}\ {\isacharsemicolon}{\isacharsemicolon}\ L\ r\isactrlisub {\isadigit{2}}{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}erule\ quot{\isacharunderscore}seq{\isacharunderscore}finiteI{\isacharcomma}\ simp{\isacharparenright}\isanewline
+\ \ \isacommand{with}\isamarkupfalse%
+\ prems\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}case\ \isacommand{by}\isamarkupfalse%
+\ simp\isanewline
+\isacommand{next}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{case}\isamarkupfalse%
+\ {\isacharparenleft}ALT\ r\isactrlisub {\isadigit{1}}\ r\isactrlisub {\isadigit{2}}{\isacharparenright}\isanewline
+\ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}{\isasymlbrakk}finite\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isasymapprox}{\isacharparenleft}L\ r\isactrlisub {\isadigit{1}}{\isacharparenright}{\isacharparenright}{\isacharsemicolon}\ finite\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isasymapprox}{\isacharparenleft}L\ r\isactrlisub {\isadigit{2}}{\isacharparenright}{\isacharparenright}{\isasymrbrakk}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ {\isasymLongrightarrow}\ finite\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isasymapprox}{\isacharparenleft}L\ r\isactrlisub {\isadigit{1}}\ {\isasymunion}\ L\ r\isactrlisub {\isadigit{2}}{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}erule\ quot{\isacharunderscore}union{\isacharunderscore}finiteI{\isacharcomma}\ simp{\isacharparenright}\isanewline
+\ \ \isacommand{with}\isamarkupfalse%
+\ prems\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}case\ \isacommand{by}\isamarkupfalse%
+\ simp\ \ \isanewline
+\isacommand{next}\isamarkupfalse%
+\isanewline
+\ \ \isacommand{case}\isamarkupfalse%
+\ {\isacharparenleft}STAR\ r{\isacharparenright}\isanewline
+\ \ \isacommand{have}\isamarkupfalse%
+\ {\isachardoublequoteopen}finite\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isasymapprox}{\isacharparenleft}L\ r{\isacharparenright}{\isacharparenright}\ \isanewline
+\ \ \ \ \ \ \ \ \ \ \ \ {\isasymLongrightarrow}\ finite\ {\isacharparenleft}UNIV\ {\isacharslash}{\isacharslash}\ {\isasymapprox}{\isacharparenleft}{\isacharparenleft}L\ r{\isacharparenright}{\isasymstar}{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ \ \ \isacommand{by}\isamarkupfalse%
+\ {\isacharparenleft}erule\ quot{\isacharunderscore}star{\isacharunderscore}finiteI{\isacharparenright}\isanewline
+\ \ \isacommand{with}\isamarkupfalse%
+\ prems\ \isacommand{show}\isamarkupfalse%
+\ {\isacharquery}case\ \isacommand{by}\isamarkupfalse%
+\ simp\isanewline
+\isacommand{qed}\isamarkupfalse%
+%
+\endisatagproof
+{\isafoldproof}%
+%
+\isadelimproof
+\ \isanewline
+%
+\endisadelimproof
+%
+\isadelimtheory
+\isanewline
+%
+\endisadelimtheory
+%
+\isatagtheory
+\isacommand{end}\isamarkupfalse%
+%
+\endisatagtheory
+{\isafoldtheory}%
+%
+\isadelimtheory
+\isanewline
+%
+\endisadelimtheory
+\isanewline
+\end{isabellebody}%
+%%% Local Variables:
+%%% mode: latex
+%%% TeX-master: "root"
+%%% End:
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/tphols-2011/generated/isabelle.sty Mon Jan 24 11:29:55 2011 +0000
@@ -0,0 +1,215 @@
+%%
+%% macros for Isabelle generated LaTeX output
+%%
+
+%%% Simple document preparation (based on theory token language and symbols)
+
+% isabelle environments
+
+\newcommand{\isabellecontext}{UNKNOWN}
+
+\newcommand{\isastyle}{\UNDEF}
+\newcommand{\isastyleminor}{\UNDEF}
+\newcommand{\isastylescript}{\UNDEF}
+\newcommand{\isastyletext}{\normalsize\rm}
+\newcommand{\isastyletxt}{\rm}
+\newcommand{\isastylecmt}{\rm}
+
+%symbol markup -- \emph achieves decent spacing via italic corrections
+\newcommand{\isamath}[1]{\emph{$#1$}}
+\newcommand{\isatext}[1]{\emph{#1}}
+\DeclareRobustCommand{\isascriptstyle}{\def\isamath##1{##1}\def\isatext##1{\mbox{\isastylescript##1}}}
+\newcommand{\isactrlsub}[1]{\emph{\isascriptstyle${}\sb{#1}$}}
+\newcommand{\isactrlsup}[1]{\emph{\isascriptstyle${}\sp{#1}$}}
+\newcommand{\isactrlisub}[1]{\emph{\isascriptstyle${}\sb{#1}$}}
+\newcommand{\isactrlisup}[1]{\emph{\isascriptstyle${}\sp{#1}$}}
+\DeclareRobustCommand{\isactrlbsub}{\emph\bgroup\math{}\sb\bgroup\mbox\bgroup\isastylescript}
+\DeclareRobustCommand{\isactrlesub}{\egroup\egroup\endmath\egroup}
+\DeclareRobustCommand{\isactrlbsup}{\emph\bgroup\math{}\sp\bgroup\mbox\bgroup\isastylescript}
+\DeclareRobustCommand{\isactrlesup}{\egroup\egroup\endmath\egroup}
+\newcommand{\isactrlbold}[1]{{\bfseries\upshape\boldmath#1}}
+\newcommand{\isactrlloc}[1]{{\bfseries\upshape\boldmath#1}}
+
+\newenvironment{isaantiq}{{\isacharat\isacharbraceleft}}{{\isacharbraceright}}
+\newcommand{\isaantiqopen}{\isakeyword{\isacharbraceleft}}
+\newcommand{\isaantiqclose}{\isakeyword{\isacharbraceright}}
+
+\newdimen\isa@parindent\newdimen\isa@parskip
+
+\newenvironment{isabellebody}{%
+\isamarkuptrue\par%
+\isa@parindent\parindent\parindent0pt%
+\isa@parskip\parskip\parskip0pt%
+\isastyle}{\par}
+
+\newenvironment{isabelle}
+{\begin{trivlist}\begin{isabellebody}\item\relax}
+{\end{isabellebody}\end{trivlist}}
+
+\newcommand{\isa}[1]{\emph{\isastyleminor #1}}
+
+\newcommand{\isaindent}[1]{\hphantom{#1}}
+\newcommand{\isanewline}{\mbox{}\par\mbox{}}
+\newcommand{\isasep}{}
+\newcommand{\isadigit}[1]{#1}
+
+\newcommand{\isachardefaults}{%
+\chardef\isacharbang=`\!%
+\chardef\isachardoublequote=`\"%
+\chardef\isachardoublequoteopen=`\"%
+\chardef\isachardoublequoteclose=`\"%
+\chardef\isacharhash=`\#%
+\chardef\isachardollar=`\$%
+\chardef\isacharpercent=`\%%
+\chardef\isacharampersand=`\&%
+\chardef\isacharprime=`\'%
+\chardef\isacharparenleft=`\(%
+\chardef\isacharparenright=`\)%
+\chardef\isacharasterisk=`\*%
+\chardef\isacharplus=`\+%
+\chardef\isacharcomma=`\,%
+\chardef\isacharminus=`\-%
+\chardef\isachardot=`\.%
+\chardef\isacharslash=`\/%
+\chardef\isacharcolon=`\:%
+\chardef\isacharsemicolon=`\;%
+\chardef\isacharless=`\<%
+\chardef\isacharequal=`\=%
+\chardef\isachargreater=`\>%
+\chardef\isacharquery=`\?%
+\chardef\isacharat=`\@%
+\chardef\isacharbrackleft=`\[%
+\chardef\isacharbackslash=`\\%
+\chardef\isacharbrackright=`\]%
+\chardef\isacharcircum=`\^%
+\chardef\isacharunderscore=`\_%
+\def\isacharunderscorekeyword{\_}%
+\chardef\isacharbackquote=`\`%
+\chardef\isacharbackquoteopen=`\`%
+\chardef\isacharbackquoteclose=`\`%
+\chardef\isacharbraceleft=`\{%
+\chardef\isacharbar=`\|%
+\chardef\isacharbraceright=`\}%
+\chardef\isachartilde=`\~%
+\def\isacharverbatimopen{\isacharbraceleft\isacharasterisk}%
+\def\isacharverbatimclose{\isacharasterisk\isacharbraceright}%
+}
+
+
+% keyword and section markup
+
+\newcommand{\isakeyword}[1]
+{\emph{\bf\def\isachardot{.}\def\isacharunderscore{\isacharunderscorekeyword}%
+\def\isacharbraceleft{\{}\def\isacharbraceright{\}}#1}}
+\newcommand{\isacommand}[1]{\isakeyword{#1}}
+
+\newcommand{\isamarkupheader}[1]{\section{#1}}
+\newcommand{\isamarkupchapter}[1]{\chapter{#1}}
+\newcommand{\isamarkupsection}[1]{\section{#1}}
+\newcommand{\isamarkupsubsection}[1]{\subsection{#1}}
+\newcommand{\isamarkupsubsubsection}[1]{\subsubsection{#1}}
+\newcommand{\isamarkupsect}[1]{\section{#1}}
+\newcommand{\isamarkupsubsect}[1]{\subsection{#1}}
+\newcommand{\isamarkupsubsubsect}[1]{\subsubsection{#1}}
+
+\newif\ifisamarkup
+\newcommand{\isabeginpar}{\par\ifisamarkup\relax\else\medskip\fi}
+\newcommand{\isaendpar}{\par\medskip}
+\newenvironment{isapar}{\parindent\isa@parindent\parskip\isa@parskip\isabeginpar}{\isaendpar}
+\newenvironment{isamarkuptext}{\par\isastyletext\begin{isapar}}{\end{isapar}}
+\newenvironment{isamarkuptxt}{\par\isastyletxt\begin{isapar}}{\end{isapar}}
+\newcommand{\isamarkupcmt}[1]{{\isastylecmt--- #1}}
+
+
+% styles
+
+\def\isabellestyle#1{\csname isabellestyle#1\endcsname}
+
+\newcommand{\isabellestyledefault}{%
+\renewcommand{\isastyle}{\small\tt\slshape}%
+\renewcommand{\isastyleminor}{\small\tt\slshape}%
+\renewcommand{\isastylescript}{\footnotesize\tt\slshape}%
+\isachardefaults%
+}
+\isabellestyledefault
+
+\newcommand{\isabellestylett}{%
+\renewcommand{\isastyle}{\small\tt}%
+\renewcommand{\isastyleminor}{\small\tt}%
+\renewcommand{\isastylescript}{\footnotesize\tt}%
+\isachardefaults%
+}
+
+\newcommand{\isabellestyleit}{%
+\renewcommand{\isastyle}{\small\it}%
+\renewcommand{\isastyleminor}{\it}%
+\renewcommand{\isastylescript}{\footnotesize\it}%
+\renewcommand{\isacharunderscorekeyword}{\mbox{-}}%
+\renewcommand{\isacharbang}{\isamath{!}}%
+\renewcommand{\isachardoublequote}{}%
+\renewcommand{\isachardoublequoteopen}{}%
+\renewcommand{\isachardoublequoteclose}{}%
+\renewcommand{\isacharhash}{\isamath{\#}}%
+\renewcommand{\isachardollar}{\isamath{\$}}%
+\renewcommand{\isacharpercent}{\isamath{\%}}%
+\renewcommand{\isacharampersand}{\isamath{\&}}%
+\renewcommand{\isacharprime}{\isamath{\mskip2mu{'}\mskip-2mu}}%
+\renewcommand{\isacharparenleft}{\isamath{(}}%
+\renewcommand{\isacharparenright}{\isamath{)}}%
+\renewcommand{\isacharasterisk}{\isamath{*}}%
+\renewcommand{\isacharplus}{\isamath{+}}%
+\renewcommand{\isacharcomma}{\isamath{\mathord,}}%
+\renewcommand{\isacharminus}{\isamath{-}}%
+\renewcommand{\isachardot}{\isamath{\mathord.}}%
+\renewcommand{\isacharslash}{\isamath{/}}%
+\renewcommand{\isacharcolon}{\isamath{\mathord:}}%
+\renewcommand{\isacharsemicolon}{\isamath{\mathord;}}%
+\renewcommand{\isacharless}{\isamath{<}}%
+\renewcommand{\isacharequal}{\isamath{=}}%
+\renewcommand{\isachargreater}{\isamath{>}}%
+\renewcommand{\isacharat}{\isamath{@}}%
+\renewcommand{\isacharbrackleft}{\isamath{[}}%
+\renewcommand{\isacharbackslash}{\isamath{\backslash}}%
+\renewcommand{\isacharbrackright}{\isamath{]}}%
+\renewcommand{\isacharunderscore}{\mbox{-}}%
+\renewcommand{\isacharbraceleft}{\isamath{\{}}%
+\renewcommand{\isacharbar}{\isamath{\mid}}%
+\renewcommand{\isacharbraceright}{\isamath{\}}}%
+\renewcommand{\isachartilde}{\isamath{{}\sp{\sim}}}%
+\renewcommand{\isacharbackquoteopen}{\isatext{\raise.3ex\hbox{$\scriptscriptstyle\langle$}}}%
+\renewcommand{\isacharbackquoteclose}{\isatext{\raise.3ex\hbox{$\scriptscriptstyle\rangle$}}}%
+\renewcommand{\isacharverbatimopen}{\isamath{\langle\!\langle}}%
+\renewcommand{\isacharverbatimclose}{\isamath{\rangle\!\rangle}}%
+}
+
+\newcommand{\isabellestylesl}{%
+\isabellestyleit%
+\renewcommand{\isastyle}{\small\sl}%
+\renewcommand{\isastyleminor}{\sl}%
+\renewcommand{\isastylescript}{\footnotesize\sl}%
+}
+
+
+% tagged regions
+
+%plain TeX version of comment package -- much faster!
+\let\isafmtname\fmtname\def\fmtname{plain}
+\usepackage{comment}
+\let\fmtname\isafmtname
+
+\newcommand{\isafold}[1]{\emph{$\langle\mathord{\mathit{#1}}\rangle$}}
+
+\newcommand{\isakeeptag}[1]%
+{\includecomment{isadelim#1}\includecomment{isatag#1}\csarg\def{isafold#1}{}}
+\newcommand{\isadroptag}[1]%
+{\excludecomment{isadelim#1}\excludecomment{isatag#1}\csarg\def{isafold#1}{}}
+\newcommand{\isafoldtag}[1]%
+{\includecomment{isadelim#1}\excludecomment{isatag#1}\csarg\def{isafold#1}{\isafold{#1}}}
+
+\isakeeptag{theory}
+\isakeeptag{proof}
+\isakeeptag{ML}
+\isakeeptag{visible}
+\isadroptag{invisible}
+
+\IfFileExists{isabelletags.sty}{\usepackage{isabelletags}}{}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/tphols-2011/generated/isabellesym.sty Mon Jan 24 11:29:55 2011 +0000
@@ -0,0 +1,358 @@
+%%
+%% definitions of standard Isabelle symbols
+%%
+
+\newcommand{\isasymzero}{\isamath{\mathbf{0}}} %requires amssymb
+\newcommand{\isasymone}{\isamath{\mathbf{1}}} %requires amssymb
+\newcommand{\isasymtwo}{\isamath{\mathbf{2}}} %requires amssymb
+\newcommand{\isasymthree}{\isamath{\mathbf{3}}} %requires amssymb
+\newcommand{\isasymfour}{\isamath{\mathbf{4}}} %requires amssymb
+\newcommand{\isasymfive}{\isamath{\mathbf{5}}} %requires amssymb
+\newcommand{\isasymsix}{\isamath{\mathbf{6}}} %requires amssymb
+\newcommand{\isasymseven}{\isamath{\mathbf{7}}} %requires amssymb
+\newcommand{\isasymeight}{\isamath{\mathbf{8}}} %requires amssymb
+\newcommand{\isasymnine}{\isamath{\mathbf{9}}} %requires amssymb
+\newcommand{\isasymA}{\isamath{\mathcal{A}}}
+\newcommand{\isasymB}{\isamath{\mathcal{B}}}
+\newcommand{\isasymC}{\isamath{\mathcal{C}}}
+\newcommand{\isasymD}{\isamath{\mathcal{D}}}
+\newcommand{\isasymE}{\isamath{\mathcal{E}}}
+\newcommand{\isasymF}{\isamath{\mathcal{F}}}
+\newcommand{\isasymG}{\isamath{\mathcal{G}}}
+\newcommand{\isasymH}{\isamath{\mathcal{H}}}
+\newcommand{\isasymI}{\isamath{\mathcal{I}}}
+\newcommand{\isasymJ}{\isamath{\mathcal{J}}}
+\newcommand{\isasymK}{\isamath{\mathcal{K}}}
+\newcommand{\isasymL}{\isamath{\mathcal{L}}}
+\newcommand{\isasymM}{\isamath{\mathcal{M}}}
+\newcommand{\isasymN}{\isamath{\mathcal{N}}}
+\newcommand{\isasymO}{\isamath{\mathcal{O}}}
+\newcommand{\isasymP}{\isamath{\mathcal{P}}}
+\newcommand{\isasymQ}{\isamath{\mathcal{Q}}}
+\newcommand{\isasymR}{\isamath{\mathcal{R}}}
+\newcommand{\isasymS}{\isamath{\mathcal{S}}}
+\newcommand{\isasymT}{\isamath{\mathcal{T}}}
+\newcommand{\isasymU}{\isamath{\mathcal{U}}}
+\newcommand{\isasymV}{\isamath{\mathcal{V}}}
+\newcommand{\isasymW}{\isamath{\mathcal{W}}}
+\newcommand{\isasymX}{\isamath{\mathcal{X}}}
+\newcommand{\isasymY}{\isamath{\mathcal{Y}}}
+\newcommand{\isasymZ}{\isamath{\mathcal{Z}}}
+\newcommand{\isasyma}{\isamath{\mathrm{a}}}
+\newcommand{\isasymb}{\isamath{\mathrm{b}}}
+\newcommand{\isasymc}{\isamath{\mathrm{c}}}
+\newcommand{\isasymd}{\isamath{\mathrm{d}}}
+\newcommand{\isasyme}{\isamath{\mathrm{e}}}
+\newcommand{\isasymf}{\isamath{\mathrm{f}}}
+\newcommand{\isasymg}{\isamath{\mathrm{g}}}
+\newcommand{\isasymh}{\isamath{\mathrm{h}}}
+\newcommand{\isasymi}{\isamath{\mathrm{i}}}
+\newcommand{\isasymj}{\isamath{\mathrm{j}}}
+\newcommand{\isasymk}{\isamath{\mathrm{k}}}
+\newcommand{\isasyml}{\isamath{\mathrm{l}}}
+\newcommand{\isasymm}{\isamath{\mathrm{m}}}
+\newcommand{\isasymn}{\isamath{\mathrm{n}}}
+\newcommand{\isasymo}{\isamath{\mathrm{o}}}
+\newcommand{\isasymp}{\isamath{\mathrm{p}}}
+\newcommand{\isasymq}{\isamath{\mathrm{q}}}
+\newcommand{\isasymr}{\isamath{\mathrm{r}}}
+\newcommand{\isasyms}{\isamath{\mathrm{s}}}
+\newcommand{\isasymt}{\isamath{\mathrm{t}}}
+\newcommand{\isasymu}{\isamath{\mathrm{u}}}
+\newcommand{\isasymv}{\isamath{\mathrm{v}}}
+\newcommand{\isasymw}{\isamath{\mathrm{w}}}
+\newcommand{\isasymx}{\isamath{\mathrm{x}}}
+\newcommand{\isasymy}{\isamath{\mathrm{y}}}
+\newcommand{\isasymz}{\isamath{\mathrm{z}}}
+\newcommand{\isasymAA}{\isamath{\mathfrak{A}}} %requires eufrak
+\newcommand{\isasymBB}{\isamath{\mathfrak{B}}} %requires eufrak
+\newcommand{\isasymCC}{\isamath{\mathfrak{C}}} %requires eufrak
+\newcommand{\isasymDD}{\isamath{\mathfrak{D}}} %requires eufrak
+\newcommand{\isasymEE}{\isamath{\mathfrak{E}}} %requires eufrak
+\newcommand{\isasymFF}{\isamath{\mathfrak{F}}} %requires eufrak
+\newcommand{\isasymGG}{\isamath{\mathfrak{G}}} %requires eufrak
+\newcommand{\isasymHH}{\isamath{\mathfrak{H}}} %requires eufrak
+\newcommand{\isasymII}{\isamath{\mathfrak{I}}} %requires eufrak
+\newcommand{\isasymJJ}{\isamath{\mathfrak{J}}} %requires eufrak
+\newcommand{\isasymKK}{\isamath{\mathfrak{K}}} %requires eufrak
+\newcommand{\isasymLL}{\isamath{\mathfrak{L}}} %requires eufrak
+\newcommand{\isasymMM}{\isamath{\mathfrak{M}}} %requires eufrak
+\newcommand{\isasymNN}{\isamath{\mathfrak{N}}} %requires eufrak
+\newcommand{\isasymOO}{\isamath{\mathfrak{O}}} %requires eufrak
+\newcommand{\isasymPP}{\isamath{\mathfrak{P}}} %requires eufrak
+\newcommand{\isasymQQ}{\isamath{\mathfrak{Q}}} %requires eufrak
+\newcommand{\isasymRR}{\isamath{\mathfrak{R}}} %requires eufrak
+\newcommand{\isasymSS}{\isamath{\mathfrak{S}}} %requires eufrak
+\newcommand{\isasymTT}{\isamath{\mathfrak{T}}} %requires eufrak
+\newcommand{\isasymUU}{\isamath{\mathfrak{U}}} %requires eufrak
+\newcommand{\isasymVV}{\isamath{\mathfrak{V}}} %requires eufrak
+\newcommand{\isasymWW}{\isamath{\mathfrak{W}}} %requires eufrak
+\newcommand{\isasymXX}{\isamath{\mathfrak{X}}} %requires eufrak
+\newcommand{\isasymYY}{\isamath{\mathfrak{Y}}} %requires eufrak
+\newcommand{\isasymZZ}{\isamath{\mathfrak{Z}}} %requires eufrak
+\newcommand{\isasymaa}{\isamath{\mathfrak{a}}} %requires eufrak
+\newcommand{\isasymbb}{\isamath{\mathfrak{b}}} %requires eufrak
+\newcommand{\isasymcc}{\isamath{\mathfrak{c}}} %requires eufrak
+\newcommand{\isasymdd}{\isamath{\mathfrak{d}}} %requires eufrak
+\newcommand{\isasymee}{\isamath{\mathfrak{e}}} %requires eufrak
+\newcommand{\isasymff}{\isamath{\mathfrak{f}}} %requires eufrak
+\newcommand{\isasymgg}{\isamath{\mathfrak{g}}} %requires eufrak
+\newcommand{\isasymhh}{\isamath{\mathfrak{h}}} %requires eufrak
+\newcommand{\isasymii}{\isamath{\mathfrak{i}}} %requires eufrak
+\newcommand{\isasymjj}{\isamath{\mathfrak{j}}} %requires eufrak
+\newcommand{\isasymkk}{\isamath{\mathfrak{k}}} %requires eufrak
+\newcommand{\isasymll}{\isamath{\mathfrak{l}}} %requires eufrak
+\newcommand{\isasymmm}{\isamath{\mathfrak{m}}} %requires eufrak
+\newcommand{\isasymnn}{\isamath{\mathfrak{n}}} %requires eufrak
+\newcommand{\isasymoo}{\isamath{\mathfrak{o}}} %requires eufrak
+\newcommand{\isasympp}{\isamath{\mathfrak{p}}} %requires eufrak
+\newcommand{\isasymqq}{\isamath{\mathfrak{q}}} %requires eufrak
+\newcommand{\isasymrr}{\isamath{\mathfrak{r}}} %requires eufrak
+\newcommand{\isasymss}{\isamath{\mathfrak{s}}} %requires eufrak
+\newcommand{\isasymtt}{\isamath{\mathfrak{t}}} %requires eufrak
+\newcommand{\isasymuu}{\isamath{\mathfrak{u}}} %requires eufrak
+\newcommand{\isasymvv}{\isamath{\mathfrak{v}}} %requires eufrak
+\newcommand{\isasymww}{\isamath{\mathfrak{w}}} %requires eufrak
+\newcommand{\isasymxx}{\isamath{\mathfrak{x}}} %requires eufrak
+\newcommand{\isasymyy}{\isamath{\mathfrak{y}}} %requires eufrak
+\newcommand{\isasymzz}{\isamath{\mathfrak{z}}} %requires eufrak
+\newcommand{\isasymalpha}{\isamath{\alpha}}
+\newcommand{\isasymbeta}{\isamath{\beta}}
+\newcommand{\isasymgamma}{\isamath{\gamma}}
+\newcommand{\isasymdelta}{\isamath{\delta}}
+\newcommand{\isasymepsilon}{\isamath{\varepsilon}}
+\newcommand{\isasymzeta}{\isamath{\zeta}}
+\newcommand{\isasymeta}{\isamath{\eta}}
+\newcommand{\isasymtheta}{\isamath{\vartheta}}
+\newcommand{\isasymiota}{\isamath{\iota}}
+\newcommand{\isasymkappa}{\isamath{\kappa}}
+\newcommand{\isasymlambda}{\isamath{\lambda}}
+\newcommand{\isasymmu}{\isamath{\mu}}
+\newcommand{\isasymnu}{\isamath{\nu}}
+\newcommand{\isasymxi}{\isamath{\xi}}
+\newcommand{\isasympi}{\isamath{\pi}}
+\newcommand{\isasymrho}{\isamath{\varrho}}
+\newcommand{\isasymsigma}{\isamath{\sigma}}
+\newcommand{\isasymtau}{\isamath{\tau}}
+\newcommand{\isasymupsilon}{\isamath{\upsilon}}
+\newcommand{\isasymphi}{\isamath{\varphi}}
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+\newcommand{\isasymrightleftharpoons}{\isamath{\rightleftharpoons}}
+\newcommand{\isasymleadsto}{\isamath{\leadsto}} %requires amssymb
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+\newcommand{\isasymdownharpoonright}{\isamath{\downharpoonright}} %requires amssymb
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+\newcommand{\isasymrestriction}{\isamath{\restriction}} %requires amssymb
+\newcommand{\isasymColon}{\isamath{\mathrel{::}}}
+\newcommand{\isasymup}{\isamath{\uparrow}}
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+\newcommand{\isasymdown}{\isamath{\downarrow}}
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+\newcommand{\isasymUpdown}{\isamath{\Updownarrow}}
+\newcommand{\isasymlangle}{\isamath{\langle}}
+\newcommand{\isasymrangle}{\isamath{\rangle}}
+\newcommand{\isasymlceil}{\isamath{\lceil}}
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+\newcommand{\isasymrbrace}{\isamath{\mathclose{\mid\mkern-4.5mu\rbrace}}}
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+\newcommand{\isasymand}{\isamath{\wedge}}
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+\newcommand{\isasymforall}{\isamath{\forall\,}}
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+\newcommand{\isasymuplus}{\isamath{\uplus}}
+\newcommand{\isasymUplus}{\isamath{\biguplus\,}}
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+\newcommand{\isasymfrown}{\isamath{\frown}}
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+\newcommand{\isasymddagger}{\isamath{\ddagger}}
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+\newcommand{\isasymunrhd}{\isamath{\unrhd}} %requires amssymb
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+\newcommand{\isasymtriangleright}{\isamath{\triangleright}}
+\newcommand{\isasymtriangle}{\isamath{\triangle}}
+\newcommand{\isasymtriangleq}{\isamath{\triangleq}} %requires amssymb
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+\newcommand{\isasymOplus}{\isamath{\bigoplus\,}}
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+\newcommand{\isasymSum}{\isamath{\sum\,}}
+\newcommand{\isasymProd}{\isamath{\prod\,}}
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+\newcommand{\isasyminfinity}{\isamath{\infty}}
+\newcommand{\isasymintegral}{\isamath{\int\,}}
+\newcommand{\isasymointegral}{\isamath{\oint\,}}
+\newcommand{\isasymclubsuit}{\isamath{\clubsuit}}
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+\newcommand{\isasymheartsuit}{\isamath{\heartsuit}}
+\newcommand{\isasymspadesuit}{\isamath{\spadesuit}}
+\newcommand{\isasymaleph}{\isamath{\aleph}}
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+\newcommand{\isasymIm}{\isamath{\Im}}
+\newcommand{\isasymflat}{\isamath{\flat}}
+\newcommand{\isasymnatural}{\isamath{\natural}}
+\newcommand{\isasymsharp}{\isamath{\sharp}}
+\newcommand{\isasymangle}{\isamath{\angle}}
+\newcommand{\isasymcopyright}{\isatext{\rm\copyright}}
+\newcommand{\isasymregistered}{\isatext{\rm\textregistered}}
+\newcommand{\isasymhyphen}{\isatext{\rm-}}
+\newcommand{\isasyminverse}{\isamath{{}^{-1}}}
+\newcommand{\isasymonesuperior}{\isamath{\mathonesuperior}} %requires latin1
+\newcommand{\isasymonequarter}{\isatext{\rm\textonequarter}} %requires latin1
+\newcommand{\isasymtwosuperior}{\isamath{\mathtwosuperior}} %requires latin1
+\newcommand{\isasymonehalf}{\isatext{\rm\textonehalf}} %requires latin1
+\newcommand{\isasymthreesuperior}{\isamath{\maththreesuperior}} %requires latin1
+\newcommand{\isasymthreequarters}{\isatext{\rm\textthreequarters}} %requires latin1
+\newcommand{\isasymordfeminine}{\isatext{\rm\textordfeminine}}
+\newcommand{\isasymordmasculine}{\isatext{\rm\textordmasculine}}
+\newcommand{\isasymsection}{\isatext{\rm\S}}
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+\newcommand{\isasymquestiondown}{\isatext{\rm\textquestiondown}}
+\newcommand{\isasymeuro}{\isatext{\textgreek{\euro}}} %requires greek babel
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+\newcommand{\isasymyen}{\isatext{\yen}} %requires amssymb
+\newcommand{\isasymcent}{\isatext{\textcent}} %requires textcomp
+\newcommand{\isasymcurrency}{\isatext{\textcurrency}} %requires textcomp
+\newcommand{\isasymdegree}{\isatext{\rm\textdegree}} %requires latin1
+\newcommand{\isasymamalg}{\isamath{\amalg}}
+\newcommand{\isasymmho}{\isamath{\mho}} %requires amssymb
+\newcommand{\isasymlozenge}{\isamath{\lozenge}} %requires amssymb
+\newcommand{\isasymwp}{\isamath{\wp}}
+\newcommand{\isasymwrong}{\isamath{\wr}}
+\newcommand{\isasymstruct}{\isamath{\diamond}}
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+\newcommand{\isasymsome}{\isamath{\epsilon\,}}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/tphols-2011/generated/pdfsetup.sty Mon Jan 24 11:29:55 2011 +0000
@@ -0,0 +1,7 @@
+%%
+%% default hyperref setup (both for pdf and dvi output)
+%%
+
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/tphols-2011/generated/root.aux Mon Jan 24 11:29:55 2011 +0000
@@ -0,0 +1,25 @@
+\relax
+\ifx\hyper@anchor\@undefined
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+\gdef \contentsline#1#2#3#4{\oldcontentsline{#1}{#2}{#3}}
+\global \let \oldnewlabel\newlabel
+\gdef \newlabel#1#2{\newlabelxx{#1}#2}
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+
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+\@writefile{toc}{\contentsline {subsection}{\numberline {2.1}Proof for this direction}{9}{subsection.2.1}}
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+\@writefile{toc}{\contentsline {subsection}{\numberline {3.1}The scheme for this direction}{21}{subsection.3.1}}
+\@writefile{toc}{\contentsline {subsection}{\numberline {3.2}A small theory for list difference}{22}{subsection.3.2}}
+\@writefile{toc}{\contentsline {subsection}{\numberline {3.3}Lemmas for basic cases}{23}{subsection.3.3}}
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+\@writefile{toc}{\contentsline {subsection}{\numberline {3.7}The main lemma}{29}{subsection.3.7}}
Binary file tphols-2011/generated/root.dvi has changed
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
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+
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/tphols-2011/generated/root.out Mon Jan 24 11:29:55 2011 +0000
@@ -0,0 +1,11 @@
+\BOOKMARK [1][-]{section.1}{Preliminary definitions}{}
+\BOOKMARK [1][-]{section.2}{Direction finite partition \040regular language}{}
+\BOOKMARK [2][-]{subsection.2.1}{Proof for this direction}{section.2}
+\BOOKMARK [1][-]{section.3}{Direction: regular language finite partition}{}
+\BOOKMARK [2][-]{subsection.3.1}{The scheme for this direction}{section.3}
+\BOOKMARK [2][-]{subsection.3.2}{A small theory for list difference}{section.3}
+\BOOKMARK [2][-]{subsection.3.3}{Lemmas for basic cases}{section.3}
+\BOOKMARK [2][-]{subsection.3.4}{The case for SEQ}{section.3}
+\BOOKMARK [2][-]{subsection.3.5}{The case for ALT}{section.3}
+\BOOKMARK [2][-]{subsection.3.6}{The case for STAR}{section.3}
+\BOOKMARK [2][-]{subsection.3.7}{The main lemma}{section.3}
Binary file tphols-2011/generated/root.pdf has changed
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/tphols-2011/generated/root.tex Mon Jan 24 11:29:55 2011 +0000
@@ -0,0 +1,65 @@
+\documentclass[11pt,a4paper]{article}
+\usepackage{isabelle,isabellesym}
+\usepackage{amsmath}
+%\usepackage[pdftex]{hyperref}
+
+% further packages required for unusual symbols (see also
+% isabellesym.sty), use only when needed
+
+%\usepackage{amssymb}
+ %for \<leadsto>, \<box>, \<diamond>, \<sqsupset>, \<mho>, \<Join>,
+ %\<lhd>, \<lesssim>, \<greatersim>, \<lessapprox>, \<greaterapprox>,
+ %\<triangleq>, \<yen>, \<lozenge>
+
+%\usepackage[greek,english]{babel}
+ %option greek for \<euro>
+ %option english (default language) for \<guillemotleft>, \<guillemotright>
+
+%\usepackage[latin1]{inputenc}
+ %for \<onesuperior>, \<onequarter>, \<twosuperior>, \<onehalf>,
+ %\<threesuperior>, \<threequarters>, \<degree>
+
+%\usepackage[only,bigsqcap]{stmaryrd}
+ %for \<Sqinter>
+
+%\usepackage{eufrak}
+ %for \<AA> ... \<ZZ>, \<aa> ... \<zz> (also included in amssymb)
+
+%\usepackage{textcomp}
+ %for \<cent>, \<currency>
+
+% this should be the last package used
+\usepackage{pdfsetup}
+
+% urls in roman style, theory text in math-similar italics
+\urlstyle{rm}
+\isabellestyle{it}
+
+% for uniform font size
+%\renewcommand{\isastyle}{\isastyleminor}
+
+
+\begin{document}
+
+\title{tphols-2011}
+\author{By xingyuan}
+\maketitle
+
+\tableofcontents
+
+% sane default for proof documents
+\parindent 0pt\parskip 0.5ex
+
+% generated text of all theories
+\input{session}
+
+% optional bibliography
+%\bibliographystyle{abbrv}
+%\bibliography{root}
+
+\end{document}
+
+%%% Local Variables:
+%%% mode: latex
+%%% TeX-master: t
+%%% End:
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/tphols-2011/generated/root.toc Mon Jan 24 11:29:55 2011 +0000
@@ -0,0 +1,11 @@
+\contentsline {section}{\numberline {1}Preliminary definitions}{1}{section.1}
+\contentsline {section}{\numberline {2}Direction \emph {\it finite\ partition\ {\emph {$\Rightarrow $}}\ regular\ language}}{5}{section.2}
+\contentsline {subsection}{\numberline {2.1}Proof for this direction}{9}{subsection.2.1}
+\contentsline {section}{\numberline {3}Direction: \emph {\it regular\ language\ {\emph {$\Rightarrow $}}finite\ partition}}{21}{section.3}
+\contentsline {subsection}{\numberline {3.1}The scheme for this direction}{21}{subsection.3.1}
+\contentsline {subsection}{\numberline {3.2}A small theory for list difference}{22}{subsection.3.2}
+\contentsline {subsection}{\numberline {3.3}Lemmas for basic cases}{23}{subsection.3.3}
+\contentsline {subsection}{\numberline {3.4}The case for \emph {\it SEQ}}{24}{subsection.3.4}
+\contentsline {subsection}{\numberline {3.5}The case for \emph {\it ALT}}{26}{subsection.3.5}
+\contentsline {subsection}{\numberline {3.6}The case for \emph {\it STAR}}{27}{subsection.3.6}
+\contentsline {subsection}{\numberline {3.7}The main lemma}{29}{subsection.3.7}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/tphols-2011/generated/session.tex Mon Jan 24 11:29:55 2011 +0000
@@ -0,0 +1,6 @@
+\input{Myhill.tex}
+
+%%% Local Variables:
+%%% mode: latex
+%%% TeX-master: "root"
+%%% End:
Binary file tphols-2011/myhill.pdf has changed