diff -r aecf1ddf3541 -r c27f04bb2262 thys3/Positions.thy
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/thys3/Positions.thy	Wed Jun 29 12:38:05 2022 +0100
@@ -0,0 +1,773 @@
+   
+theory Positions
+  imports PosixSpec Lexer
+begin
+
+chapter \<open>An alternative definition for POSIX values\<close>
+
+section \<open>Positions in Values\<close>
+
+fun 
+  at :: "val \<Rightarrow> nat list \<Rightarrow> val"
+where
+  "at v [] = v"
+| "at (Left v) (0#ps)= at v ps"
+| "at (Right v) (Suc 0#ps)= at v ps"
+| "at (Seq v1 v2) (0#ps)= at v1 ps"
+| "at (Seq v1 v2) (Suc 0#ps)= at v2 ps"
+| "at (Stars vs) (n#ps)= at (nth vs n) ps"
+
+
+
+fun Pos :: "val \<Rightarrow> (nat list) set"
+where
+  "Pos (Void) = {[]}"
+| "Pos (Char c) = {[]}"
+| "Pos (Left v) = {[]} \<union> {0#ps | ps. ps \<in> Pos v}"
+| "Pos (Right v) = {[]} \<union> {1#ps | ps. ps \<in> Pos v}"
+| "Pos (Seq v1 v2) = {[]} \<union> {0#ps | ps. ps \<in> Pos v1} \<union> {1#ps | ps. ps \<in> Pos v2}" 
+| "Pos (Stars []) = {[]}"
+| "Pos (Stars (v#vs)) = {[]} \<union> {0#ps | ps. ps \<in> Pos v} \<union> {Suc n#ps | n ps. n#ps \<in> Pos (Stars vs)}"
+
+
+lemma Pos_stars:
+  "Pos (Stars vs) = {[]} \<union> (\<Union>n < length vs. {n#ps | ps. ps \<in> Pos (vs ! n)})"
+apply(induct vs)
+apply(auto simp add: insert_ident less_Suc_eq_0_disj)
+done
+
+lemma Pos_empty:
+  shows "[] \<in> Pos v"
+by (induct v rule: Pos.induct)(auto)
+
+
+abbreviation
+  "intlen vs \<equiv> int (length vs)"
+
+
+definition pflat_len :: "val \<Rightarrow> nat list => int"
+where
+  "pflat_len v p \<equiv> (if p \<in> Pos v then intlen (flat (at v p)) else -1)"
+
+lemma pflat_len_simps:
+  shows "pflat_len (Seq v1 v2) (0#p) = pflat_len v1 p"
+  and   "pflat_len (Seq v1 v2) (Suc 0#p) = pflat_len v2 p"
+  and   "pflat_len (Left v) (0#p) = pflat_len v p"
+  and   "pflat_len (Left v) (Suc 0#p) = -1"
+  and   "pflat_len (Right v) (Suc 0#p) = pflat_len v p"
+  and   "pflat_len (Right v) (0#p) = -1"
+  and   "pflat_len (Stars (v#vs)) (Suc n#p) = pflat_len (Stars vs) (n#p)"
+  and   "pflat_len (Stars (v#vs)) (0#p) = pflat_len v p"
+  and   "pflat_len v [] = intlen (flat v)"
+by (auto simp add: pflat_len_def Pos_empty)
+
+lemma pflat_len_Stars_simps:
+  assumes "n < length vs"
+  shows "pflat_len (Stars vs) (n#p) = pflat_len (vs!n) p"
+using assms
+apply(induct vs arbitrary: n p)
+apply(auto simp add: less_Suc_eq_0_disj pflat_len_simps)
+done
+
+lemma pflat_len_outside:
+  assumes "p \<notin> Pos v1"
+  shows "pflat_len v1 p = -1 "
+using assms by (simp add: pflat_len_def)
+
+
+
+section \<open>Orderings\<close>
+
+
+definition prefix_list:: "'a list \<Rightarrow> 'a list \<Rightarrow> bool" ("_ \<sqsubseteq>pre _" [60,59] 60)
+where
+  "ps1 \<sqsubseteq>pre ps2 \<equiv> \<exists>ps'. ps1 @ps' = ps2"
+
+definition sprefix_list:: "'a list \<Rightarrow> 'a list \<Rightarrow> bool" ("_ \<sqsubset>spre _" [60,59] 60)
+where
+  "ps1 \<sqsubset>spre ps2 \<equiv> ps1 \<sqsubseteq>pre ps2 \<and> ps1 \<noteq> ps2"
+
+inductive lex_list :: "nat list \<Rightarrow> nat list \<Rightarrow> bool" ("_ \<sqsubset>lex _" [60,59] 60)
+where
+  "[] \<sqsubset>lex (p#ps)"
+| "ps1 \<sqsubset>lex ps2 \<Longrightarrow> (p#ps1) \<sqsubset>lex (p#ps2)"
+| "p1 < p2 \<Longrightarrow> (p1#ps1) \<sqsubset>lex (p2#ps2)"
+
+lemma lex_irrfl:
+  fixes ps1 ps2 :: "nat list"
+  assumes "ps1 \<sqsubset>lex ps2"
+  shows "ps1 \<noteq> ps2"
+using assms
+by(induct rule: lex_list.induct)(auto)
+
+lemma lex_simps [simp]:
+  fixes xs ys :: "nat list"
+  shows "[] \<sqsubset>lex ys \<longleftrightarrow> ys \<noteq> []"
+  and   "xs \<sqsubset>lex [] \<longleftrightarrow> False"
+  and   "(x # xs) \<sqsubset>lex (y # ys) \<longleftrightarrow> (x < y \<or> (x = y \<and> xs \<sqsubset>lex ys))"
+by (auto simp add: neq_Nil_conv elim: lex_list.cases intro: lex_list.intros)
+
+lemma lex_trans:
+  fixes ps1 ps2 ps3 :: "nat list"
+  assumes "ps1 \<sqsubset>lex ps2" "ps2 \<sqsubset>lex ps3"
+  shows "ps1 \<sqsubset>lex ps3"
+using assms
+by (induct arbitrary: ps3 rule: lex_list.induct)
+   (auto elim: lex_list.cases)
+
+
+lemma lex_trichotomous:
+  fixes p q :: "nat list"
+  shows "p = q \<or> p \<sqsubset>lex q \<or> q \<sqsubset>lex p"
+apply(induct p arbitrary: q)
+apply(auto elim: lex_list.cases)
+apply(case_tac q)
+apply(auto)
+done
+
+
+
+
+section \<open>POSIX Ordering of Values According to Okui \& Suzuki\<close>
+
+
+definition PosOrd:: "val \<Rightarrow> nat list \<Rightarrow> val \<Rightarrow> bool" ("_ \<sqsubset>val _ _" [60, 60, 59] 60)
+where
+  "v1 \<sqsubset>val p v2 \<equiv> pflat_len v1 p > pflat_len v2 p \<and>
+                   (\<forall>q \<in> Pos v1 \<union> Pos v2. q \<sqsubset>lex p \<longrightarrow> pflat_len v1 q = pflat_len v2 q)"
+
+lemma PosOrd_def2:
+  shows "v1 \<sqsubset>val p v2 \<longleftrightarrow> 
+         pflat_len v1 p > pflat_len v2 p \<and>
+         (\<forall>q \<in> Pos v1. q \<sqsubset>lex p \<longrightarrow> pflat_len v1 q = pflat_len v2 q) \<and>
+         (\<forall>q \<in> Pos v2. q \<sqsubset>lex p \<longrightarrow> pflat_len v1 q = pflat_len v2 q)"
+unfolding PosOrd_def
+apply(auto)
+done
+
+
+definition PosOrd_ex:: "val \<Rightarrow> val \<Rightarrow> bool" ("_ :\<sqsubset>val _" [60, 59] 60)
+where
+  "v1 :\<sqsubset>val v2 \<equiv> \<exists>p. v1 \<sqsubset>val p v2"
+
+definition PosOrd_ex_eq:: "val \<Rightarrow> val \<Rightarrow> bool" ("_ :\<sqsubseteq>val _" [60, 59] 60)
+where
+  "v1 :\<sqsubseteq>val v2 \<equiv> v1 :\<sqsubset>val v2 \<or> v1 = v2"
+
+
+lemma PosOrd_trans:
+  assumes "v1 :\<sqsubset>val v2" "v2 :\<sqsubset>val v3"
+  shows "v1 :\<sqsubset>val v3"
+proof -
+  from assms obtain p p'
+    where as: "v1 \<sqsubset>val p v2" "v2 \<sqsubset>val p' v3" unfolding PosOrd_ex_def by blast
+  then have pos: "p \<in> Pos v1" "p' \<in> Pos v2" unfolding PosOrd_def pflat_len_def
+    by (smt not_int_zless_negative)+
+  have "p = p' \<or> p \<sqsubset>lex p' \<or> p' \<sqsubset>lex p"
+    by (rule lex_trichotomous)
+  moreover
+    { assume "p = p'"
+      with as have "v1 \<sqsubset>val p v3" unfolding PosOrd_def pflat_len_def
+      by (smt Un_iff)
+      then have " v1 :\<sqsubset>val v3" unfolding PosOrd_ex_def by blast
+    }   
+  moreover
+    { assume "p \<sqsubset>lex p'"
+      with as have "v1 \<sqsubset>val p v3" unfolding PosOrd_def pflat_len_def
+      by (smt Un_iff lex_trans)
+      then have " v1 :\<sqsubset>val v3" unfolding PosOrd_ex_def by blast
+    }
+  moreover
+    { assume "p' \<sqsubset>lex p"
+      with as have "v1 \<sqsubset>val p' v3" unfolding PosOrd_def
+      by (smt Un_iff lex_trans pflat_len_def)
+      then have "v1 :\<sqsubset>val v3" unfolding PosOrd_ex_def by blast
+    }
+  ultimately show "v1 :\<sqsubset>val v3" by blast
+qed
+
+lemma PosOrd_irrefl:
+  assumes "v :\<sqsubset>val v"
+  shows "False"
+using assms unfolding PosOrd_ex_def PosOrd_def
+by auto
+
+lemma PosOrd_assym:
+  assumes "v1 :\<sqsubset>val v2" 
+  shows "\<not>(v2 :\<sqsubset>val v1)"
+using assms
+using PosOrd_irrefl PosOrd_trans by blast 
+
+(*
+  :\<sqsubseteq>val and :\<sqsubset>val are partial orders.
+*)
+
+lemma PosOrd_ordering:
+  shows "ordering (\<lambda>v1 v2. v1 :\<sqsubseteq>val v2) (\<lambda> v1 v2. v1 :\<sqsubset>val v2)"
+unfolding ordering_def PosOrd_ex_eq_def
+apply(auto)
+using PosOrd_trans partial_preordering_def apply blast
+using PosOrd_assym ordering_axioms_def by blast
+
+lemma PosOrd_order:
+  shows "class.order (\<lambda>v1 v2. v1 :\<sqsubseteq>val v2) (\<lambda> v1 v2. v1 :\<sqsubset>val v2)"
+using PosOrd_ordering
+apply(simp add: class.order_def class.preorder_def class.order_axioms_def)
+  by (metis (full_types) PosOrd_ex_eq_def PosOrd_irrefl PosOrd_trans)
+
+
+lemma PosOrd_ex_eq2:
+  shows "v1 :\<sqsubset>val v2 \<longleftrightarrow> (v1 :\<sqsubseteq>val v2 \<and> v1 \<noteq> v2)"
+  using PosOrd_ordering
+  using PosOrd_ex_eq_def PosOrd_irrefl by blast 
+
+lemma PosOrdeq_trans:
+  assumes "v1 :\<sqsubseteq>val v2" "v2 :\<sqsubseteq>val v3"
+  shows "v1 :\<sqsubseteq>val v3"
+using assms PosOrd_ordering 
+  unfolding ordering_def
+  by (metis partial_preordering.trans)
+
+lemma PosOrdeq_antisym:
+  assumes "v1 :\<sqsubseteq>val v2" "v2 :\<sqsubseteq>val v1"
+  shows "v1 = v2"
+using assms PosOrd_ordering 
+  unfolding ordering_def
+  by (simp add: ordering_axioms_def)
+
+lemma PosOrdeq_refl:
+  shows "v :\<sqsubseteq>val v" 
+unfolding PosOrd_ex_eq_def
+by auto
+
+
+lemma PosOrd_shorterE:
+  assumes "v1 :\<sqsubset>val v2" 
+  shows "length (flat v2) \<le> length (flat v1)"
+using assms unfolding PosOrd_ex_def PosOrd_def
+apply(auto)
+apply(case_tac p)
+apply(simp add: pflat_len_simps)
+apply(drule_tac x="[]" in bspec)
+apply(simp add: Pos_empty)
+apply(simp add: pflat_len_simps)
+done
+
+lemma PosOrd_shorterI:
+  assumes "length (flat v2) < length (flat v1)"
+  shows "v1 :\<sqsubset>val v2"
+unfolding PosOrd_ex_def PosOrd_def pflat_len_def 
+using assms Pos_empty by force
+
+lemma PosOrd_spreI:
+  assumes "flat v' \<sqsubset>spre flat v"
+  shows "v :\<sqsubset>val v'" 
+using assms
+apply(rule_tac PosOrd_shorterI)
+unfolding prefix_list_def sprefix_list_def
+by (metis append_Nil2 append_eq_conv_conj drop_all le_less_linear)
+
+lemma pflat_len_inside:
+  assumes "pflat_len v2 p < pflat_len v1 p"
+  shows "p \<in> Pos v1"
+using assms 
+unfolding pflat_len_def
+by (auto split: if_splits)
+
+
+lemma PosOrd_Left_Right:
+  assumes "flat v1 = flat v2"
+  shows "Left v1 :\<sqsubset>val Right v2" 
+unfolding PosOrd_ex_def
+apply(rule_tac x="[0]" in exI)
+apply(auto simp add: PosOrd_def pflat_len_simps assms)
+done
+
+lemma PosOrd_LeftE:
+  assumes "Left v1 :\<sqsubset>val Left v2" "flat v1 = flat v2"
+  shows "v1 :\<sqsubset>val v2"
+using assms
+unfolding PosOrd_ex_def PosOrd_def2
+apply(auto simp add: pflat_len_simps)
+apply(frule pflat_len_inside)
+apply(auto simp add: pflat_len_simps)
+by (metis lex_simps(3) pflat_len_simps(3))
+
+lemma PosOrd_LeftI:
+  assumes "v1 :\<sqsubset>val v2" "flat v1 = flat v2"
+  shows  "Left v1 :\<sqsubset>val Left v2"
+using assms
+unfolding PosOrd_ex_def PosOrd_def2
+apply(auto simp add: pflat_len_simps)
+by (metis less_numeral_extra(3) lex_simps(3) pflat_len_simps(3))
+
+lemma PosOrd_Left_eq:
+  assumes "flat v1 = flat v2"
+  shows "Left v1 :\<sqsubset>val Left v2 \<longleftrightarrow> v1 :\<sqsubset>val v2" 
+using assms PosOrd_LeftE PosOrd_LeftI
+by blast
+
+
+lemma PosOrd_RightE:
+  assumes "Right v1 :\<sqsubset>val Right v2" "flat v1 = flat v2"
+  shows "v1 :\<sqsubset>val v2"
+using assms
+unfolding PosOrd_ex_def PosOrd_def2
+apply(auto simp add: pflat_len_simps)
+apply(frule pflat_len_inside)
+apply(auto simp add: pflat_len_simps)
+by (metis lex_simps(3) pflat_len_simps(5))
+
+lemma PosOrd_RightI:
+  assumes "v1 :\<sqsubset>val v2" "flat v1 = flat v2"
+  shows  "Right v1 :\<sqsubset>val Right v2"
+using assms
+unfolding PosOrd_ex_def PosOrd_def2
+apply(auto simp add: pflat_len_simps)
+by (metis lex_simps(3) nat_neq_iff pflat_len_simps(5))
+
+
+lemma PosOrd_Right_eq:
+  assumes "flat v1 = flat v2"
+  shows "Right v1 :\<sqsubset>val Right v2 \<longleftrightarrow> v1 :\<sqsubset>val v2" 
+using assms PosOrd_RightE PosOrd_RightI
+by blast
+
+
+lemma PosOrd_SeqI1:
+  assumes "v1 :\<sqsubset>val w1" "flat (Seq v1 v2) = flat (Seq w1 w2)"
+  shows "Seq v1 v2 :\<sqsubset>val Seq w1 w2" 
+using assms(1)
+apply(subst (asm) PosOrd_ex_def)
+apply(subst (asm) PosOrd_def)
+apply(clarify)
+apply(subst PosOrd_ex_def)
+apply(rule_tac x="0#p" in exI)
+apply(subst PosOrd_def)
+apply(rule conjI)
+apply(simp add: pflat_len_simps)
+apply(rule ballI)
+apply(rule impI)
+apply(simp only: Pos.simps)
+apply(auto)[1]
+apply(simp add: pflat_len_simps)
+apply(auto simp add: pflat_len_simps)
+using assms(2)
+apply(simp)
+apply(metis length_append of_nat_add)
+done
+
+lemma PosOrd_SeqI2:
+  assumes "v2 :\<sqsubset>val w2" "flat v2 = flat w2"
+  shows "Seq v v2 :\<sqsubset>val Seq v w2" 
+using assms(1)
+apply(subst (asm) PosOrd_ex_def)
+apply(subst (asm) PosOrd_def)
+apply(clarify)
+apply(subst PosOrd_ex_def)
+apply(rule_tac x="Suc 0#p" in exI)
+apply(subst PosOrd_def)
+apply(rule conjI)
+apply(simp add: pflat_len_simps)
+apply(rule ballI)
+apply(rule impI)
+apply(simp only: Pos.simps)
+apply(auto)[1]
+apply(simp add: pflat_len_simps)
+using assms(2)
+apply(simp)
+apply(auto simp add: pflat_len_simps)
+done
+
+lemma PosOrd_Seq_eq:
+  assumes "flat v2 = flat w2"
+  shows "(Seq v v2) :\<sqsubset>val (Seq v w2) \<longleftrightarrow> v2 :\<sqsubset>val w2"
+using assms 
+apply(auto)
+prefer 2
+apply(simp add: PosOrd_SeqI2)
+apply(simp add: PosOrd_ex_def)
+apply(auto)
+apply(case_tac p)
+apply(simp add: PosOrd_def pflat_len_simps)
+apply(case_tac a)
+apply(simp add: PosOrd_def pflat_len_simps)
+apply(clarify)
+apply(case_tac nat)
+prefer 2
+apply(simp add: PosOrd_def pflat_len_simps pflat_len_outside)
+apply(rule_tac x="list" in exI)
+apply(auto simp add: PosOrd_def2 pflat_len_simps)
+apply(smt Collect_disj_eq lex_list.intros(2) mem_Collect_eq pflat_len_simps(2))
+apply(smt Collect_disj_eq lex_list.intros(2) mem_Collect_eq pflat_len_simps(2))
+done
+
+
+
+lemma PosOrd_StarsI:
+  assumes "v1 :\<sqsubset>val v2" "flats (v1#vs1) = flats (v2#vs2)"
+  shows "Stars (v1#vs1) :\<sqsubset>val Stars (v2#vs2)" 
+using assms(1)
+apply(subst (asm) PosOrd_ex_def)
+apply(subst (asm) PosOrd_def)
+apply(clarify)
+apply(subst PosOrd_ex_def)
+apply(subst PosOrd_def)
+apply(rule_tac x="0#p" in exI)
+apply(simp add: pflat_len_Stars_simps pflat_len_simps)
+using assms(2)
+apply(simp add: pflat_len_simps)
+apply(auto simp add: pflat_len_Stars_simps pflat_len_simps)
+by (metis length_append of_nat_add)
+
+lemma PosOrd_StarsI2:
+  assumes "Stars vs1 :\<sqsubset>val Stars vs2" "flats vs1 = flats vs2"
+  shows "Stars (v#vs1) :\<sqsubset>val Stars (v#vs2)" 
+using assms(1)
+apply(subst (asm) PosOrd_ex_def)
+apply(subst (asm) PosOrd_def)
+apply(clarify)
+apply(subst PosOrd_ex_def)
+apply(subst PosOrd_def)
+apply(case_tac p)
+apply(simp add: pflat_len_simps)
+apply(rule_tac x="Suc a#list" in exI)
+apply(auto simp add: pflat_len_Stars_simps pflat_len_simps assms(2))
+done
+
+lemma PosOrd_Stars_appendI:
+  assumes "Stars vs1 :\<sqsubset>val Stars vs2" "flat (Stars vs1) = flat (Stars vs2)"
+  shows "Stars (vs @ vs1) :\<sqsubset>val Stars (vs @ vs2)"
+using assms
+apply(induct vs)
+apply(simp)
+apply(simp add: PosOrd_StarsI2)
+done
+
+lemma PosOrd_StarsE2:
+  assumes "Stars (v # vs1) :\<sqsubset>val Stars (v # vs2)"
+  shows "Stars vs1 :\<sqsubset>val Stars vs2"
+using assms
+apply(subst (asm) PosOrd_ex_def)
+apply(erule exE)
+apply(case_tac p)
+apply(simp)
+apply(simp add: PosOrd_def pflat_len_simps)
+apply(subst PosOrd_ex_def)
+apply(rule_tac x="[]" in exI)
+apply(simp add: PosOrd_def pflat_len_simps Pos_empty)
+apply(simp)
+apply(case_tac a)
+apply(clarify)
+apply(auto simp add: pflat_len_simps PosOrd_def pflat_len_def split: if_splits)[1]
+apply(clarify)
+apply(simp add: PosOrd_ex_def)
+apply(rule_tac x="nat#list" in exI)
+apply(auto simp add: PosOrd_def pflat_len_simps)[1]
+apply(case_tac q)
+apply(simp add: PosOrd_def pflat_len_simps)
+apply(clarify)
+apply(drule_tac x="Suc a # lista" in bspec)
+apply(simp)
+apply(auto simp add: PosOrd_def pflat_len_simps)[1]
+apply(case_tac q)
+apply(simp add: PosOrd_def pflat_len_simps)
+apply(clarify)
+apply(drule_tac x="Suc a # lista" in bspec)
+apply(simp)
+apply(auto simp add: PosOrd_def pflat_len_simps)[1]
+done
+
+lemma PosOrd_Stars_appendE:
+  assumes "Stars (vs @ vs1) :\<sqsubset>val Stars (vs @ vs2)"
+  shows "Stars vs1 :\<sqsubset>val Stars vs2"
+using assms
+apply(induct vs)
+apply(simp)
+apply(simp add: PosOrd_StarsE2)
+done
+
+lemma PosOrd_Stars_append_eq:
+  assumes "flats vs1 = flats vs2"
+  shows "Stars (vs @ vs1) :\<sqsubset>val Stars (vs @ vs2) \<longleftrightarrow> Stars vs1 :\<sqsubset>val Stars vs2"
+using assms
+apply(rule_tac iffI)
+apply(erule PosOrd_Stars_appendE)
+apply(rule PosOrd_Stars_appendI)
+apply(auto)
+done  
+
+lemma PosOrd_almost_trichotomous:
+  shows "v1 :\<sqsubset>val v2 \<or> v2 :\<sqsubset>val v1 \<or> (length (flat v1) = length (flat v2))"
+apply(auto simp add: PosOrd_ex_def)
+apply(auto simp add: PosOrd_def)
+apply(rule_tac x="[]" in exI)
+apply(auto simp add: Pos_empty pflat_len_simps)
+apply(drule_tac x="[]" in spec)
+apply(auto simp add: Pos_empty pflat_len_simps)
+done
+
+
+
+section \<open>The Posix Value is smaller than any other Value\<close>
+
+
+lemma Posix_PosOrd:
+  assumes "s \<in> r \<rightarrow> v1" "v2 \<in> LV r s" 
+  shows "v1 :\<sqsubseteq>val v2"
+using assms
+proof (induct arbitrary: v2 rule: Posix.induct)
+  case (Posix_ONE v)
+  have "v \<in> LV ONE []" by fact
+  then have "v = Void"
+    by (simp add: LV_simps)
+  then show "Void :\<sqsubseteq>val v"
+    by (simp add: PosOrd_ex_eq_def)
+next
+  case (Posix_CH c v)
+  have "v \<in> LV (CH c) [c]" by fact
+  then have "v = Char c"
+    by (simp add: LV_simps)
+  then show "Char c :\<sqsubseteq>val v"
+    by (simp add: PosOrd_ex_eq_def)
+next
+  case (Posix_ALT1 s r1 v r2 v2)
+  have as1: "s \<in> r1 \<rightarrow> v" by fact
+  have IH: "\<And>v2. v2 \<in> LV r1 s \<Longrightarrow> v :\<sqsubseteq>val v2" by fact
+  have "v2 \<in> LV (ALT r1 r2) s" by fact
+  then have "\<Turnstile> v2 : ALT r1 r2" "flat v2 = s"
+    by(auto simp add: LV_def prefix_list_def)
+  then consider
+    (Left) v3 where "v2 = Left v3" "\<Turnstile> v3 : r1" "flat v3 = s" 
+  | (Right) v3 where "v2 = Right v3" "\<Turnstile> v3 : r2" "flat v3 = s"
+  by (auto elim: Prf.cases)
+  then show "Left v :\<sqsubseteq>val v2"
+  proof(cases)
+     case (Left v3)
+     have "v3 \<in> LV r1 s" using Left(2,3) 
+       by (auto simp add: LV_def prefix_list_def)
+     with IH have "v :\<sqsubseteq>val v3" by simp
+     moreover
+     have "flat v3 = flat v" using as1 Left(3)
+       by (simp add: Posix1(2)) 
+     ultimately have "Left v :\<sqsubseteq>val Left v3"
+       by (simp add: PosOrd_ex_eq_def PosOrd_Left_eq)
+     then show "Left v :\<sqsubseteq>val v2" unfolding Left .
+  next
+     case (Right v3)
+     have "flat v3 = flat v" using as1 Right(3)
+       by (simp add: Posix1(2)) 
+     then have "Left v :\<sqsubseteq>val Right v3" 
+       unfolding PosOrd_ex_eq_def
+       by (simp add: PosOrd_Left_Right)
+     then show "Left v :\<sqsubseteq>val v2" unfolding Right .
+  qed
+next
+  case (Posix_ALT2 s r2 v r1 v2)
+  have as1: "s \<in> r2 \<rightarrow> v" by fact
+  have as2: "s \<notin> L r1" by fact
+  have IH: "\<And>v2. v2 \<in> LV r2 s \<Longrightarrow> v :\<sqsubseteq>val v2" by fact
+  have "v2 \<in> LV (ALT r1 r2) s" by fact
+  then have "\<Turnstile> v2 : ALT r1 r2" "flat v2 = s"
+    by(auto simp add: LV_def prefix_list_def)
+  then consider
+    (Left) v3 where "v2 = Left v3" "\<Turnstile> v3 : r1" "flat v3 = s" 
+  | (Right) v3 where "v2 = Right v3" "\<Turnstile> v3 : r2" "flat v3 = s"
+  by (auto elim: Prf.cases)
+  then show "Right v :\<sqsubseteq>val v2"
+  proof (cases)
+    case (Right v3)
+     have "v3 \<in> LV r2 s" using Right(2,3) 
+       by (auto simp add: LV_def prefix_list_def)
+     with IH have "v :\<sqsubseteq>val v3" by simp
+     moreover
+     have "flat v3 = flat v" using as1 Right(3)
+       by (simp add: Posix1(2)) 
+     ultimately have "Right v :\<sqsubseteq>val Right v3" 
+        by (auto simp add: PosOrd_ex_eq_def PosOrd_RightI)
+     then show "Right v :\<sqsubseteq>val v2" unfolding Right .
+  next
+     case (Left v3)
+     have "v3 \<in> LV r1 s" using Left(2,3) as2  
+       by (auto simp add: LV_def prefix_list_def)
+     then have "flat v3 = flat v \<and> \<Turnstile> v3 : r1" using as1 Left(3)
+       by (simp add: Posix1(2) LV_def) 
+     then have "False" using as1 as2 Left
+       by (auto simp add: Posix1(2) L_flat_Prf1)
+     then show "Right v :\<sqsubseteq>val v2" by simp
+  qed
+next 
+  case (Posix_SEQ s1 r1 v1 s2 r2 v2 v3)
+  have "s1 \<in> r1 \<rightarrow> v1" "s2 \<in> r2 \<rightarrow> v2" by fact+
+  then have as1: "s1 = flat v1" "s2 = flat v2" by (simp_all add: Posix1(2))
+  have IH1: "\<And>v3. v3 \<in> LV r1 s1 \<Longrightarrow> v1 :\<sqsubseteq>val v3" by fact
+  have IH2: "\<And>v3. v3 \<in> LV r2 s2 \<Longrightarrow> v2 :\<sqsubseteq>val v3" by fact
+  have cond: "\<not> (\<exists>s\<^sub>3 s\<^sub>4. s\<^sub>3 \<noteq> [] \<and> s\<^sub>3 @ s\<^sub>4 = s2 \<and> s1 @ s\<^sub>3 \<in> L r1 \<and> s\<^sub>4 \<in> L r2)" by fact
+  have "v3 \<in> LV (SEQ r1 r2) (s1 @ s2)" by fact
+  then obtain v3a v3b where eqs:
+    "v3 = Seq v3a v3b" "\<Turnstile> v3a : r1" "\<Turnstile> v3b : r2"
+    "flat v3a @ flat v3b = s1 @ s2" 
+    by (force simp add: prefix_list_def LV_def elim: Prf.cases)
+  with cond have "flat v3a \<sqsubseteq>pre s1" unfolding prefix_list_def
+    by (smt L_flat_Prf1 append_eq_append_conv2 append_self_conv)
+  then have "flat v3a \<sqsubset>spre s1 \<or> (flat v3a = s1 \<and> flat v3b = s2)" using eqs
+    by (simp add: sprefix_list_def append_eq_conv_conj)
+  then have q2: "v1 :\<sqsubset>val v3a \<or> (flat v3a = s1 \<and> flat v3b = s2)" 
+    using PosOrd_spreI as1(1) eqs by blast
+  then have "v1 :\<sqsubset>val v3a \<or> (v3a \<in> LV r1 s1 \<and> v3b \<in> LV r2 s2)" using eqs(2,3)
+    by (auto simp add: LV_def)
+  then have "v1 :\<sqsubset>val v3a \<or> (v1 :\<sqsubseteq>val v3a \<and> v2 :\<sqsubseteq>val v3b)" using IH1 IH2 by blast         
+  then have "Seq v1 v2 :\<sqsubseteq>val Seq v3a v3b" using eqs q2 as1
+    unfolding  PosOrd_ex_eq_def by (auto simp add: PosOrd_SeqI1 PosOrd_Seq_eq) 
+  then show "Seq v1 v2 :\<sqsubseteq>val v3" unfolding eqs by blast
+next 
+  case (Posix_STAR1 s1 r v s2 vs v3) 
+  have "s1 \<in> r \<rightarrow> v" "s2 \<in> STAR r \<rightarrow> Stars vs" by fact+
+  then have as1: "s1 = flat v" "s2 = flat (Stars vs)" by (auto dest: Posix1(2))
+  have IH1: "\<And>v3. v3 \<in> LV r s1 \<Longrightarrow> v :\<sqsubseteq>val v3" by fact
+  have IH2: "\<And>v3. v3 \<in> LV (STAR r) s2 \<Longrightarrow> Stars vs :\<sqsubseteq>val v3" by fact
+  have cond: "\<not> (\<exists>s\<^sub>3 s\<^sub>4. s\<^sub>3 \<noteq> [] \<and> s\<^sub>3 @ s\<^sub>4 = s2 \<and> s1 @ s\<^sub>3 \<in> L r \<and> s\<^sub>4 \<in> L (STAR r))" by fact
+  have cond2: "flat v \<noteq> []" by fact
+  have "v3 \<in> LV (STAR r) (s1 @ s2)" by fact
+  then consider 
+    (NonEmpty) v3a vs3 where "v3 = Stars (v3a # vs3)" 
+    "\<Turnstile> v3a : r" "\<Turnstile> Stars vs3 : STAR r"
+    "flat (Stars (v3a # vs3)) = s1 @ s2"
+  | (Empty) "v3 = Stars []"
+  unfolding LV_def  
+  apply(auto)
+  apply(erule Prf.cases)
+  apply(auto)
+  apply(case_tac vs)
+  apply(auto intro: Prf.intros)
+  done
+  then show "Stars (v # vs) :\<sqsubseteq>val v3" 
+    proof (cases)
+      case (NonEmpty v3a vs3)
+      have "flat (Stars (v3a # vs3)) = s1 @ s2" using NonEmpty(4) . 
+      with cond have "flat v3a \<sqsubseteq>pre s1" using NonEmpty(2,3)
+        unfolding prefix_list_def
+        by (smt L_flat_Prf1 append_Nil2 append_eq_append_conv2 flat.simps(7)) 
+      then have "flat v3a \<sqsubset>spre s1 \<or> (flat v3a = s1 \<and> flat (Stars vs3) = s2)" using NonEmpty(4)
+        by (simp add: sprefix_list_def append_eq_conv_conj)
+      then have q2: "v :\<sqsubset>val v3a \<or> (flat v3a = s1 \<and> flat (Stars vs3) = s2)" 
+        using PosOrd_spreI as1(1) NonEmpty(4) by blast
+      then have "v :\<sqsubset>val v3a \<or> (v3a \<in> LV r s1 \<and> Stars vs3 \<in> LV (STAR r) s2)" 
+        using NonEmpty(2,3) by (auto simp add: LV_def)
+      then have "v :\<sqsubset>val v3a \<or> (v :\<sqsubseteq>val v3a \<and> Stars vs :\<sqsubseteq>val Stars vs3)" using IH1 IH2 by blast
+      then have "v :\<sqsubset>val v3a \<or> (v = v3a \<and> Stars vs :\<sqsubseteq>val Stars vs3)" 
+         unfolding PosOrd_ex_eq_def by auto     
+      then have "Stars (v # vs) :\<sqsubseteq>val Stars (v3a # vs3)" using NonEmpty(4) q2 as1
+        unfolding  PosOrd_ex_eq_def
+        using PosOrd_StarsI PosOrd_StarsI2 by auto 
+      then show "Stars (v # vs) :\<sqsubseteq>val v3" unfolding NonEmpty by blast
+    next 
+      case Empty
+      have "v3 = Stars []" by fact
+      then show "Stars (v # vs) :\<sqsubseteq>val v3"
+      unfolding PosOrd_ex_eq_def using cond2
+      by (simp add: PosOrd_shorterI)
+    qed      
+next 
+  case (Posix_STAR2 r v2)
+  have "v2 \<in> LV (STAR r) []" by fact
+  then have "v2 = Stars []" 
+    unfolding LV_def by (auto elim: Prf.cases) 
+  then show "Stars [] :\<sqsubseteq>val v2"
+  by (simp add: PosOrd_ex_eq_def)
+qed
+
+
+lemma Posix_PosOrd_reverse:
+  assumes "s \<in> r \<rightarrow> v1" 
+  shows "\<not>(\<exists>v2 \<in> LV r s. v2 :\<sqsubset>val v1)"
+using assms
+by (metis Posix_PosOrd less_irrefl PosOrd_def 
+    PosOrd_ex_eq_def PosOrd_ex_def PosOrd_trans)
+
+lemma PosOrd_Posix:
+  assumes "v1 \<in> LV r s" "\<forall>v\<^sub>2 \<in> LV r s. \<not> v\<^sub>2 :\<sqsubset>val v1"
+  shows "s \<in> r \<rightarrow> v1" 
+proof -
+  have "s \<in> L r" using assms(1) unfolding LV_def
+    using L_flat_Prf1 by blast 
+  then obtain vposix where vp: "s \<in> r \<rightarrow> vposix"
+    using lexer_correct_Some by blast 
+  with assms(1) have "vposix :\<sqsubseteq>val v1" by (simp add: Posix_PosOrd) 
+  then have "vposix = v1 \<or> vposix :\<sqsubset>val v1" unfolding PosOrd_ex_eq2 by auto
+  moreover
+    { assume "vposix :\<sqsubset>val v1"
+      moreover
+      have "vposix \<in> LV r s" using vp 
+         using Posix_LV by blast 
+      ultimately have "False" using assms(2) by blast
+    }
+  ultimately show "s \<in> r \<rightarrow> v1" using vp by blast
+qed
+
+lemma Least_existence:
+  assumes "LV r s \<noteq> {}"
+  shows " \<exists>vmin \<in> LV r s. \<forall>v \<in> LV r s. vmin :\<sqsubseteq>val v"
+proof -
+  from assms
+  obtain vposix where "s \<in> r \<rightarrow> vposix"
+  unfolding LV_def 
+  using L_flat_Prf1 lexer_correct_Some by blast
+  then have "\<forall>v \<in> LV r s. vposix :\<sqsubseteq>val v"
+    by (simp add: Posix_PosOrd)
+  then show "\<exists>vmin \<in> LV r s. \<forall>v \<in> LV r s. vmin :\<sqsubseteq>val v"
+    using Posix_LV \<open>s \<in> r \<rightarrow> vposix\<close> by blast
+qed 
+
+lemma Least_existence1:
+  assumes "LV r s \<noteq> {}"
+  shows " \<exists>!vmin \<in> LV r s. \<forall>v \<in> LV r s. vmin :\<sqsubseteq>val v"
+using Least_existence[OF assms] assms
+using PosOrdeq_antisym by blast
+
+lemma Least_existence2:
+  assumes "LV r s \<noteq> {}"
+  shows " \<exists>!vmin \<in> LV r s. lexer r s = Some vmin \<and> (\<forall>v \<in> LV r s. vmin :\<sqsubseteq>val v)"
+using Least_existence[OF assms] assms
+using PosOrdeq_antisym 
+  using PosOrd_Posix PosOrd_ex_eq2 lexer_correctness(1) by auto
+
+
+lemma Least_existence1_pre:
+  assumes "LV r s \<noteq> {}"
+  shows " \<exists>!vmin \<in> LV r s. \<forall>v \<in> (LV r s \<union> {v'. flat v' \<sqsubset>spre s}). vmin :\<sqsubseteq>val v"
+using Least_existence[OF assms] assms
+apply -
+apply(erule bexE)
+apply(rule_tac a="vmin" in ex1I)
+apply(auto)[1]
+apply (metis PosOrd_Posix PosOrd_ex_eq2 PosOrd_spreI PosOrdeq_antisym Posix1(2))
+apply(auto)[1]
+apply(simp add: PosOrdeq_antisym)
+done
+
+lemma
+  shows "partial_order_on UNIV {(v1, v2). v1 :\<sqsubseteq>val v2}"
+apply(simp add: partial_order_on_def)
+apply(simp add: preorder_on_def refl_on_def)
+apply(simp add: PosOrdeq_refl)
+apply(auto)
+apply(rule transI)
+apply(auto intro: PosOrdeq_trans)[1]
+apply(rule antisymI)
+apply(simp add: PosOrdeq_antisym)
+done
+
+lemma
+ "wf {(v1, v2). v1 :\<sqsubset>val v2 \<and> v1 \<in> LV r s \<and> v2 \<in> LV r s}"
+apply(rule finite_acyclic_wf)
+prefer 2
+apply(simp add: acyclic_def)
+apply(induct_tac rule: trancl.induct)
+apply(auto)[1]
+oops
+
+
+unused_thms
+
+end
\ No newline at end of file