diff -r b794db0b79db -r b1258b7d2789 Attic/old/My.thy
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Attic/old/My.thy	Mon Jul 25 13:33:38 2011 +0000
@@ -0,0 +1,389 @@
+theory My
+imports Main Infinite_Set
+begin
+
+
+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}"
+
+inductive_set
+  Star :: "string set \<Rightarrow> string set" ("_\<star>" [101] 102)
+  for L :: "string set"
+where
+  start[intro]: "[] \<in> L\<star>"
+| step[intro]:  "\<lbrakk>s1 \<in> L; s2 \<in> L\<star>\<rbrakk> \<Longrightarrow> s1@s2 \<in> L\<star>"
+
+lemma lang_star_cases:
+  shows "L\<star> =  {[]} \<union> L ;; L\<star>"
+unfolding Seq_def
+by (auto) (metis Star.simps)
+
+lemma lang_star_cases2:
+  shows "L ;; L\<star>  = L\<star> ;; L"
+sorry
+
+
+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
+next
+  assume "X = X ;; A \<union> B"
+  then have "B \<subseteq> X" "X ;; A \<subseteq> X" by auto
+  show "X = B ;; A\<star>" sorry
+qed
+
+datatype rexp =
+  NULL
+| EMPTY
+| CHAR char
+| SEQ rexp rexp
+| ALT rexp rexp
+| STAR rexp
+
+fun
+  Sem :: "rexp \<Rightarrow> string set" ("\<lparr>_\<rparr>" [0] 1000)
+where
+    "\<lparr>NULL\<rparr> = {}"
+  | "\<lparr>EMPTY\<rparr> = {[]}"
+  | "\<lparr>CHAR c\<rparr> = {[c]}"
+  | "\<lparr>SEQ r1 r2\<rparr> = \<lparr>r1\<rparr> ;; \<lparr>r2\<rparr>"
+  | "\<lparr>ALT r1 r2\<rparr> = \<lparr>r1\<rparr> \<union> \<lparr>r2\<rparr>"
+  | "\<lparr>STAR r\<rparr> = \<lparr>r\<rparr>\<star>"
+
+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"
+
+lemma folds_simp_null [simp]:
+  "finite rs \<Longrightarrow> x \<in> \<lparr>folds ALT NULL rs\<rparr> \<longleftrightarrow> (\<exists>r \<in> rs. x \<in> \<lparr>r\<rparr>)"
+apply (simp add: folds_def)
+apply (rule someI2_ex)
+apply (erule finite_imp_fold_graph)
+apply (erule fold_graph.induct)
+apply (auto)
+done
+
+lemma folds_simp_empty [simp]:
+  "finite rs \<Longrightarrow> x \<in> \<lparr>folds ALT EMPTY rs\<rparr> \<longleftrightarrow> (\<exists>r \<in> rs. x \<in> \<lparr>r\<rparr>) \<or> x = []"
+apply (simp add: folds_def)
+apply (rule someI2_ex)
+apply (erule finite_imp_fold_graph)
+apply (erule fold_graph.induct)
+apply (auto)
+done
+
+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)"
+
+definition
+  str_eq_rel ("\<approx>_")
+where
+  "\<approx>Lang \<equiv> {(x, y). x \<approx>Lang y}"
+
+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)"
+
+lemma lang_is_union_of_finals: 
+  "Lang = \<Union> {X. final X Lang}"
+proof -
+  have  "Lang \<subseteq> \<Union> {X. final X Lang}"
+    unfolding final_def
+    unfolding quotient_def Image_def
+    unfolding str_eq_rel_def
+    apply(simp)
+    apply(auto)
+    apply(rule_tac x="(\<approx>Lang) `` {x}" in exI)
+    unfolding Image_def
+    unfolding str_eq_rel_def
+    apply(auto)
+    unfolding str_eq_def
+    apply(auto)
+    apply(drule_tac x="[]" in spec)
+    apply(simp)
+    done
+  moreover
+  have "\<Union>{X. final X Lang} \<subseteq> Lang" 
+    unfolding final_def by auto
+  ultimately 
+  show "Lang = \<Union> {X. final X Lang}"
+    by blast
+qed
+
+lemma all_rexp:
+  "\<lbrakk>finite (UNIV // \<approx>Lang); X \<in> (UNIV // \<approx>Lang)\<rbrakk> \<Longrightarrow> \<exists>r. X = \<lparr>r\<rparr>"
+sorry
+
+lemma final_rexp:
+  "\<lbrakk>finite (UNIV // (\<approx>Lang)); final X Lang\<rbrakk> \<Longrightarrow> \<exists>r. X = \<lparr>r\<rparr>"
+unfolding final_def
+using all_rexp by blast
+
+lemma finite_f_one_to_one:
+  assumes "finite B"
+  and "\<forall>x \<in> B. \<exists>y. f y = x"
+  shows "\<exists>rs. finite rs \<and> (B = {f y | y . y \<in> rs})"
+using assms
+by (induct) (auto)
+
+lemma finite_final:
+  assumes "finite (UNIV // (\<approx>Lang))"
+  shows "finite {X. final X Lang}"
+using assms
+proof -
+  have "{X. final X Lang} \<subseteq> (UNIV // (\<approx>Lang))"
+    unfolding final_def by auto
+  with assms show "finite {X. final X Lang}" 
+    using finite_subset by auto
+qed
+
+lemma finite_regular_aux:
+  fixes Lang :: "string set"
+  assumes "finite (UNIV // (\<approx>Lang))"
+  shows "\<exists>rs. Lang = \<lparr>folds ALT NULL rs\<rparr>"
+apply(subst lang_is_union_of_finals)
+using assms
+apply -
+apply(drule finite_final)
+apply(drule_tac f="Sem" in finite_f_one_to_one)
+apply(clarify)
+apply(drule final_rexp[OF assms])
+apply(auto)[1]
+apply(clarify)
+apply(rule_tac x="rs" in exI)
+apply(simp)
+apply(rule set_eqI)
+apply(auto)
+done
+
+lemma finite_regular:
+  fixes Lang :: "string set"
+  assumes "finite (UNIV // (\<approx>Lang))"
+  shows "\<exists>r. Lang =  \<lparr>r\<rparr>"
+using assms finite_regular_aux
+by auto
+
+
+
+section {* other direction *}
+
+
+lemma inj_image_lang:
+  fixes f::"string \<Rightarrow> 'a"
+  assumes str_inj: "\<And>x y. f x = f y \<Longrightarrow> x \<approx>Lang y"
+  shows "inj_on (image f) (UNIV // (\<approx>Lang))"
+proof - 
+  { fix x y::string
+    assume eq_tag: "f ` {z. x \<approx>Lang z} = f ` {z. y \<approx>Lang z}"
+    moreover
+    have "{z. x \<approx>Lang z} \<noteq> {}" unfolding str_eq_def by auto
+    ultimately obtain a b where "x \<approx>Lang a" "y \<approx>Lang b" "f a = f b" by blast
+    then have "x \<approx>Lang a" "y \<approx>Lang b" "a \<approx>Lang b" using str_inj by auto
+    then have "x \<approx>Lang y" unfolding str_eq_def by simp 
+    then have "{z. x \<approx>Lang z} = {z. y \<approx>Lang z}" unfolding str_eq_def by simp
+  }
+  then have "\<forall>x\<in>UNIV // \<approx>Lang. \<forall>y\<in>UNIV // \<approx>Lang. f ` x = f ` y \<longrightarrow> x = y"
+    unfolding quotient_def Image_def str_eq_rel_def by simp
+  then show "inj_on (image f) (UNIV // (\<approx>Lang))"
+    unfolding inj_on_def by simp
+qed
+
+
+lemma finite_range_image: 
+  assumes fin: "finite (range f)"
+  shows "finite ((image f) ` X)"
+proof -
+  from fin have "finite (Pow (f ` UNIV))" by auto
+  moreover
+  have "(image f) ` X \<subseteq> Pow (f ` UNIV)" by auto
+  ultimately show "finite ((image f) ` X)" using finite_subset by auto
+qed
+
+definition 
+  tag1 :: "string set \<Rightarrow> string set \<Rightarrow> string \<Rightarrow> (string set \<times> string set)"
+where
+  "tag1 L\<^isub>1 L\<^isub>2 \<equiv> \<lambda>x. ((\<approx>L\<^isub>1) `` {x}, (\<approx>L\<^isub>2) `` {x})"
+
+lemma tag1_range_finite:
+  assumes finite1: "finite (UNIV // \<approx>L\<^isub>1)"
+  and finite2: "finite (UNIV // \<approx>L\<^isub>2)"
+  shows "finite (range (tag1 L\<^isub>1 L\<^isub>2))"
+proof -
+  have "finite (UNIV // \<approx>L\<^isub>1 \<times> UNIV // \<approx>L\<^isub>2)" using finite1 finite2 by auto
+  moreover
+  have "range (tag1 L\<^isub>1 L\<^isub>2) \<subseteq> (UNIV // \<approx>L\<^isub>1) \<times> (UNIV // \<approx>L\<^isub>2)"
+    unfolding tag1_def quotient_def by auto
+  ultimately show "finite (range (tag1 L\<^isub>1 L\<^isub>2))" 
+    using finite_subset by blast
+qed
+
+lemma tag1_inj:
+  "tag1 L\<^isub>1 L\<^isub>2 x = tag1 L\<^isub>1 L\<^isub>2 y \<Longrightarrow> x \<approx>(L\<^isub>1 \<union> L\<^isub>2) y"
+unfolding tag1_def Image_def str_eq_rel_def str_eq_def
+by auto
+
+lemma quot_alt_cu:
+  fixes L\<^isub>1 L\<^isub>2::"string set"
+  assumes fin1: "finite (UNIV // \<approx>L\<^isub>1)"
+  and fin2: "finite (UNIV // \<approx>L\<^isub>2)"
+  shows "finite (UNIV // \<approx>(L\<^isub>1 \<union> L\<^isub>2))"
+proof -
+  have "finite (range (tag1 L\<^isub>1 L\<^isub>2))" 
+    using fin1 fin2 tag1_range_finite by simp
+  then have "finite (image (tag1 L\<^isub>1 L\<^isub>2) ` (UNIV // \<approx>(L\<^isub>1 \<union> L\<^isub>2)))" 
+    using finite_range_image by blast
+  moreover 
+  have "\<And>x y. tag1 L\<^isub>1 L\<^isub>2 x = tag1 L\<^isub>1 L\<^isub>2 y \<Longrightarrow> x \<approx>(L\<^isub>1 \<union> L\<^isub>2) y" 
+    using tag1_inj by simp
+  then have "inj_on (image (tag1 L\<^isub>1 L\<^isub>2)) (UNIV // \<approx>(L\<^isub>1 \<union> L\<^isub>2))" 
+    using inj_image_lang by blast
+  ultimately 
+  show "finite (UNIV // \<approx>(L\<^isub>1 \<union> L\<^isub>2))" by (rule finite_imageD)
+qed
+
+
+section {* finite \<Rightarrow> regular *}
+
+definition
+  transitions :: "string set \<Rightarrow> string set \<Rightarrow> rexp set" ("_\<Turnstile>\<Rightarrow>_")
+where
+  "Y \<Turnstile>\<Rightarrow> X \<equiv> {CHAR c | c. Y ;; {[c]} \<subseteq> X}"
+
+definition
+  transitions_rexp ("_ \<turnstile>\<rightarrow> _")
+where
+  "Y \<turnstile>\<rightarrow> X \<equiv> if [] \<in> X then folds ALT EMPTY (Y \<Turnstile>\<Rightarrow>X) else folds ALT NULL (Y \<Turnstile>\<Rightarrow>X)"
+
+definition
+  "rhs CS X \<equiv> if X = {[]} then {({[]}, EMPTY)} else {(Y, Y \<turnstile>\<rightarrow>X) | Y. Y \<in> CS}"
+
+definition
+  "rhs_sem CS X \<equiv> \<Union> {(Y;; \<lparr>r\<rparr>) | Y r . (Y, r) \<in> rhs CS X}"
+
+definition
+  "eqs CS \<equiv> (\<Union>X \<in> CS. {(X, rhs CS X)})"
+
+definition
+  "eqs_sem CS \<equiv> (\<Union>X \<in> CS. {(X, rhs_sem CS X)})"
+
+lemma [simp]:
+  shows "finite (Y \<Turnstile>\<Rightarrow> X)"
+unfolding transitions_def
+by auto
+
+
+lemma defined_by_str:
+  assumes "s \<in> X" 
+  and "X \<in> UNIV // (\<approx>Lang)"
+  shows "X = (\<approx>Lang) `` {s}"
+using assms
+unfolding quotient_def Image_def
+unfolding str_eq_rel_def str_eq_def
+by auto
+
+lemma every_eqclass_has_transition:
+  assumes has_str: "s @ [c] \<in> X"
+  and     in_CS:   "X \<in> UNIV // (\<approx>Lang)"
+  obtains Y where "Y \<in> UNIV // (\<approx>Lang)" and "Y ;; {[c]} \<subseteq> X" and "s \<in> Y"
+proof -
+  def Y \<equiv> "(\<approx>Lang) `` {s}"
+  have "Y \<in> UNIV // (\<approx>Lang)" 
+    unfolding Y_def quotient_def by auto
+  moreover
+  have "X = (\<approx>Lang) `` {s @ [c]}" 
+    using has_str in_CS defined_by_str by blast
+  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)
+  moreover
+  have "s \<in> Y" unfolding Y_def 
+    unfolding Image_def str_eq_rel_def str_eq_def by simp
+  (*moreover 
+  have "True" by simp FIXME *) 
+  ultimately show thesis by (blast intro: that)
+qed
+
+lemma test:
+  assumes "[] \<in> X"
+  shows "[] \<in> \<lparr>Y \<turnstile>\<rightarrow> X\<rparr>"
+using assms
+by (simp add: transitions_rexp_def)
+
+lemma rhs_sem:
+  assumes "X \<in> (UNIV // (\<approx>Lang))"
+  shows "X \<subseteq> rhs_sem (UNIV // (\<approx>Lang)) X"
+apply(case_tac "X = {[]}")
+apply(simp)
+apply(simp add: rhs_sem_def rhs_def Seq_def)
+apply(rule subsetI)
+apply(case_tac "x = []")
+apply(simp add: rhs_sem_def rhs_def)
+apply(rule_tac x = "X" in exI)
+apply(simp)
+apply(rule_tac x = "X" in exI)
+apply(simp add: assms)
+apply(simp add: transitions_rexp_def)
+oops
+
+
+(*
+fun
+  power :: "string \<Rightarrow> nat \<Rightarrow> string" (infixr "\<Up>" 100)
+where
+  "s \<Up> 0 = s"
+| "s \<Up> (Suc n) = s @ (s \<Up> n)"
+
+definition 
+ "Lone = {(''0'' \<Up> n) @ (''1'' \<Up> n) | n. True }"
+
+lemma
+  "infinite (UNIV // (\<approx>Lone))"
+unfolding infinite_iff_countable_subset
+apply(rule_tac x="\<lambda>n. {(''0'' \<Up> n) @ (''1'' \<Up> i) | i. i \<in> {..n} }" in exI)
+apply(auto)
+prefer 2
+unfolding Lone_def
+unfolding quotient_def
+unfolding Image_def
+apply(simp)
+unfolding str_eq_rel_def
+unfolding str_eq_def
+apply(auto)
+apply(rule_tac x="''0'' \<Up> n" in exI)
+apply(auto)
+unfolding infinite_nat_iff_unbounded
+unfolding Lone_def
+*)
+
+
+
+text {* Derivatives *}
+
+definition
+  DERS :: "string \<Rightarrow> string set \<Rightarrow> string set"
+where
+  "DERS s L \<equiv> {s'. s @ s' \<in> L}"
+
+lemma
+  shows "x \<approx>L y \<longleftrightarrow> DERS x L = DERS y L"
+unfolding DERS_def str_eq_def
+by auto
\ No newline at end of file