thys3/ClosedFormsBounds.thy
changeset 556 c27f04bb2262
parent 495 f9cdc295ccf7
child 558 671a83abccf3
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/thys3/ClosedFormsBounds.thy	Wed Jun 29 12:38:05 2022 +0100
@@ -0,0 +1,448 @@
+
+theory ClosedFormsBounds
+  imports "GeneralRegexBound" "ClosedForms"
+begin
+lemma alts_ders_lambda_shape_ders:
+  shows "\<forall>r \<in> set (map (\<lambda>r. rders_simp r ( s)) rs ). \<exists>r1 \<in> set rs. r = rders_simp r1 s"
+  by (simp add: image_iff)
+
+lemma rlist_bound:
+  assumes "\<forall>r \<in> set rs. rsize r \<le> N"
+  shows "rsizes rs \<le> N * (length rs)"
+  using assms
+  apply(induct rs)
+  apply simp
+  by simp
+
+lemma alts_closed_form_bounded: 
+  assumes "\<forall>r \<in> set rs. \<forall>s. rsize (rders_simp r s) \<le> N"
+  shows "rsize (rders_simp (RALTS rs) s) \<le> max (Suc (N * (length rs))) (rsize (RALTS rs))"
+proof (cases s)
+  case Nil
+  then show "rsize (rders_simp (RALTS rs) s) \<le> max (Suc (N * length rs)) (rsize (RALTS rs))"
+    by simp
+next
+  case (Cons a s)
+  
+  from assms have "\<forall>r \<in> set (map (\<lambda>r. rders_simp r (a # s)) rs ). rsize r \<le> N"
+    by (metis alts_ders_lambda_shape_ders)
+  then have a: "rsizes (map (\<lambda>r. rders_simp r (a # s)) rs ) \<le> N *  (length rs)"
+    by (metis length_map rlist_bound) 
+     
+  have "rsize (rders_simp (RALTS rs) (a # s)) 
+          = rsize (rsimp (RALTS (map (\<lambda>r. rders_simp r (a # s)) rs)))"
+    by (metis alts_closed_form_variant list.distinct(1)) 
+  also have "... \<le> rsize (RALTS (map (\<lambda>r. rders_simp r (a # s)) rs))"
+    using rsimp_mono by blast
+  also have "... = Suc (rsizes (map (\<lambda>r. rders_simp r (a # s)) rs))"
+    by simp
+  also have "... \<le> Suc (N * (length rs))"
+    using a by blast
+  finally have "rsize (rders_simp (RALTS rs) (a # s)) \<le> max (Suc (N * length rs)) (rsize (RALTS rs))" 
+    by auto
+  then show ?thesis using local.Cons by simp 
+qed
+
+lemma alts_simp_ineq_unfold:
+  shows "rsize (rsimp (RALTS rs)) \<le> Suc (rsizes (rdistinct (rflts (map rsimp rs)) {}))"
+  using rsimp_aalts_smaller by auto
+
+
+lemma rdistinct_mono_list:
+  shows "rsizes (rdistinct (x5 @ rs) rset) \<le> rsizes x5 + rsizes (rdistinct  rs ((set x5 ) \<union> rset))"
+  apply(induct x5 arbitrary: rs rset)
+   apply simp
+  apply(case_tac "a \<in> rset")
+   apply simp
+   apply (simp add: add.assoc insert_absorb trans_le_add2)
+  apply simp
+  by (metis Un_insert_right)
+
+
+lemma flts_size_reduction_alts:
+  assumes a: "\<And>noalts_set alts_set corr_set.
+           (\<forall>r\<in>noalts_set. \<forall>xs. r \<noteq> RALTS xs) \<and>
+           (\<forall>a\<in>alts_set. \<exists>xs. a = RALTS xs \<and> set xs \<subseteq> corr_set) \<Longrightarrow>
+           Suc (rsizes (rdistinct (rflts rs) (noalts_set \<union> corr_set)))
+           \<le> Suc (rsizes (rdistinct rs (insert RZERO (noalts_set \<union> alts_set))))"
+ and b: "\<forall>r\<in>noalts_set. \<forall>xs. r \<noteq> RALTS xs"
+ and c: "\<forall>a\<in>alts_set. \<exists>xs. a = RALTS xs \<and> set xs \<subseteq> corr_set"
+ and d: "a = RALTS x5"
+ shows "rsizes (rdistinct (rflts (a # rs)) (noalts_set \<union> corr_set))
+           \<le> rsizes (rdistinct (a # rs) (insert RZERO (noalts_set \<union> alts_set)))"
+  
+  apply(case_tac "a \<in> alts_set")
+  using a b c d
+   apply simp
+   apply(subgoal_tac "set x5 \<subseteq> corr_set")
+  apply(subst rdistinct_concat)
+  apply auto[1]
+    apply presburger
+   apply fastforce
+  using a b c d
+  apply (subgoal_tac "a \<notin> noalts_set")
+  prefer 2
+  apply blast
+  apply simp
+  apply(subgoal_tac "rsizes (rdistinct (x5 @ rflts rs) (noalts_set \<union> corr_set)) 
+                   \<le> rsizes x5 + rsizes (rdistinct (rflts rs) ((set x5) \<union> (noalts_set \<union> corr_set)))")
+  prefer 2
+  using rdistinct_mono_list apply presburger
+  apply(subgoal_tac "insert (RALTS x5) (noalts_set \<union> alts_set) = noalts_set \<union> (insert (RALTS x5) alts_set)")
+   apply(simp only:)
+  apply(subgoal_tac "rsizes x5 + rsizes (rdistinct (rflts rs) (noalts_set \<union> (corr_set \<union> (set x5)))) \<le>
+           rsizes x5 + rsizes (rdistinct rs (insert RZERO (noalts_set \<union> insert (RALTS x5) alts_set)))")
+  
+  apply (simp add: Un_left_commute inf_sup_aci(5))
+   apply(subgoal_tac "rsizes (rdistinct (rflts rs) (noalts_set \<union> (corr_set \<union> set x5))) \<le> 
+                    rsizes (rdistinct rs (insert RZERO (noalts_set \<union> insert (RALTS x5) alts_set)))")
+    apply linarith
+   apply(subgoal_tac "\<forall>r \<in> insert (RALTS x5) alts_set. \<exists>xs1.( r = RALTS xs1 \<and> set xs1 \<subseteq> corr_set \<union> set x5)")
+    apply presburger
+   apply (meson insert_iff sup.cobounded2 sup.coboundedI1)
+  by blast
+
+
+lemma flts_vs_nflts1:
+  assumes "\<forall>r \<in> noalts_set. \<forall>xs. r \<noteq> RALTS xs"
+  and "\<forall>a \<in> alts_set. (\<exists>xs. a = RALTS xs \<and> set xs \<subseteq> corr_set)" 
+  shows "rsizes (rdistinct (rflts rs) (noalts_set \<union> corr_set))
+         \<le> rsizes (rdistinct rs (insert RZERO (noalts_set \<union> alts_set)))"
+  using assms
+    apply(induct rs arbitrary: noalts_set alts_set corr_set)
+   apply simp
+  apply(case_tac a)
+       apply(case_tac "RZERO \<in> noalts_set")
+        apply simp
+       apply(subgoal_tac "RZERO \<notin> alts_set")
+        apply simp
+       apply fastforce
+      apply(case_tac "RONE \<in> noalts_set")
+       apply simp
+      apply(subgoal_tac "RONE \<notin> alts_set")
+  prefer 2
+  apply fastforce
+      apply(case_tac "RONE \<in> corr_set")
+       apply(subgoal_tac "rflts (a # rs) = RONE # rflts rs")
+        apply(simp only:)
+        apply(subgoal_tac "rdistinct (RONE # rflts rs) (noalts_set \<union> corr_set) = 
+                           rdistinct (rflts rs) (noalts_set \<union> corr_set)")
+         apply(simp only:)
+  apply(subgoal_tac "rdistinct (RONE # rs) (insert RZERO (noalts_set \<union> alts_set)) =
+                     RONE # (rdistinct rs (insert RONE (insert RZERO (noalts_set \<union> alts_set)))) ")
+          apply(simp only:)
+  apply(subgoal_tac "rdistinct (rflts rs) (noalts_set \<union> corr_set) = 
+                     rdistinct (rflts rs) (insert RONE (noalts_set \<union> corr_set))")
+  apply (simp only:)
+  apply(subgoal_tac "insert RONE (noalts_set \<union> corr_set) = (insert RONE noalts_set) \<union> corr_set")
+            apply(simp only:)
+  apply(subgoal_tac "insert RONE (insert RZERO (noalts_set \<union> alts_set)) = 
+                     insert RZERO ((insert RONE noalts_set) \<union> alts_set)")
+             apply(simp only:)
+  apply(subgoal_tac "rsizes (rdistinct rs (insert RZERO (insert RONE noalts_set \<union> alts_set)))
+                   \<le>  rsizes (RONE # rdistinct rs (insert RZERO (insert RONE noalts_set \<union> alts_set)))")
+  apply (smt (verit, best) dual_order.trans insert_iff rrexp.distinct(15))
+  apply (metis (no_types, opaque_lifting)  le_add_same_cancel2 list.simps(9) sum_list.Cons zero_le)
+            apply fastforce
+           apply fastforce
+  apply (metis Un_iff insert_absorb)
+         apply (metis UnE insertE insert_is_Un rdistinct.simps(2) rrexp.distinct(1))
+        apply (meson UnCI rdistinct.simps(2))
+  using rflts.simps(4) apply presburger
+      apply simp
+      apply(subgoal_tac "insert RONE (noalts_set \<union> corr_set) = (insert RONE noalts_set) \<union> corr_set")
+  apply(simp only:)
+  apply (metis Un_insert_left insertE rrexp.distinct(15))
+      apply fastforce
+     apply(case_tac "a \<in> noalts_set")
+      apply simp
+  apply(subgoal_tac "a \<notin> alts_set")
+      prefer 2
+      apply blast
+  apply(case_tac "a \<in> corr_set")
+      apply(subgoal_tac "noalts_set \<union> corr_set = insert a ( noalts_set  \<union> corr_set)")
+  prefer 2
+  apply fastforce
+      apply(simp only:)
+      apply(subgoal_tac "rsizes (rdistinct (a # rs) (insert RZERO ((insert a noalts_set) \<union> alts_set))) \<le>
+              rsizes (rdistinct (a # rs) (insert RZERO (noalts_set \<union> alts_set)))")
+
+       apply(subgoal_tac  "rsizes (rdistinct (rflts (a # rs)) ((insert a noalts_set) \<union> corr_set)) \<le>
+              rsizes (rdistinct (a # rs) (insert RZERO ((insert a noalts_set) \<union> alts_set)))")
+  apply fastforce
+       apply simp
+  apply(subgoal_tac "(insert a (noalts_set \<union> alts_set)) = (insert a noalts_set) \<union> alts_set")
+        apply(simp only:)
+        apply(subgoal_tac "noalts_set \<union> corr_set = (insert a noalts_set) \<union> corr_set")
+  apply(simp only:)
+  apply (metis insertE rrexp.distinct(21))
+        apply blast
+  
+  apply fastforce
+  apply force
+     apply simp
+     apply (metis Un_insert_left insert_iff rrexp.distinct(21))
+    apply(case_tac "a \<in> noalts_set")
+     apply simp
+  apply(subgoal_tac "a \<notin> alts_set")
+      prefer 2
+      apply blast
+  apply(case_tac "a \<in> corr_set")
+      apply(subgoal_tac "noalts_set \<union> corr_set = insert a ( noalts_set  \<union> corr_set)")
+  prefer 2
+  apply fastforce
+      apply(simp only:)
+      apply(subgoal_tac "rsizes (rdistinct (a # rs) (insert RZERO ((insert a noalts_set) \<union> alts_set))) \<le>
+             rsizes (rdistinct (a # rs) (insert RZERO (noalts_set \<union> alts_set)))")
+
+       apply(subgoal_tac "rsizes (rdistinct (rflts (a # rs)) ((insert a noalts_set) \<union> corr_set)) \<le>
+          rsizes (rdistinct (a # rs) (insert RZERO ((insert a noalts_set) \<union> alts_set)))")
+  apply fastforce
+       apply simp
+  apply(subgoal_tac "(insert a (noalts_set \<union> alts_set)) = (insert a noalts_set) \<union> alts_set")
+        apply(simp only:)
+        apply(subgoal_tac "noalts_set \<union> corr_set = (insert a noalts_set) \<union> corr_set")
+  apply(simp only:)
+
+
+  apply (metis insertE rrexp.distinct(25))
+  apply blast
+  apply fastforce
+  apply force
+     apply simp
+  
+    apply (metis Un_insert_left insertE rrexp.distinct(25))
+
+  using Suc_le_mono flts_size_reduction_alts apply presburger
+     apply(case_tac "a \<in> noalts_set")
+      apply simp
+  apply(subgoal_tac "a \<notin> alts_set")
+      prefer 2
+      apply blast
+  apply(case_tac "a \<in> corr_set")
+      apply(subgoal_tac "noalts_set \<union> corr_set = insert a ( noalts_set  \<union> corr_set)")
+  prefer 2
+  apply fastforce
+      apply(simp only:)
+      apply(subgoal_tac "rsizes (rdistinct (a # rs) (insert RZERO ((insert a noalts_set) \<union> alts_set))) \<le>
+               rsizes (rdistinct (a # rs) (insert RZERO (noalts_set \<union> alts_set)))")
+
+       apply(subgoal_tac "rsizes (rdistinct (rflts (a # rs)) ((insert a noalts_set) \<union> corr_set)) \<le>
+          rsizes (rdistinct (a # rs) (insert RZERO ((insert a noalts_set) \<union> alts_set)))")
+  apply fastforce
+       apply simp
+  apply(subgoal_tac "(insert a (noalts_set \<union> alts_set)) = (insert a noalts_set) \<union> alts_set")
+        apply(simp only:)
+        apply(subgoal_tac "noalts_set \<union> corr_set = (insert a noalts_set) \<union> corr_set")
+  apply(simp only:)
+  apply (metis insertE rrexp.distinct(29))
+
+        apply blast
+  
+  apply fastforce
+  apply force
+     apply simp
+  apply (metis Un_insert_left insert_iff rrexp.distinct(29))
+  done
+
+
+lemma flts_vs_nflts:
+  assumes "\<forall>r \<in> noalts_set. \<forall>xs. r \<noteq> RALTS xs"
+  and "\<forall>a \<in> alts_set. (\<exists>xs. a = RALTS xs \<and> set xs \<subseteq> corr_set)"
+  shows "rsizes (rdistinct (rflts rs) (noalts_set \<union> corr_set))
+         \<le> rsizes (rdistinct rs (insert RZERO (noalts_set \<union> alts_set)))"
+  by (simp add: assms flts_vs_nflts1)
+
+lemma distinct_simp_ineq_general:
+  assumes "rsimp ` no_simp = has_simp" "finite no_simp"
+  shows "rsizes (rdistinct (map rsimp rs) has_simp) \<le> rsizes (rdistinct rs no_simp)"
+  using assms
+  apply(induct rs no_simp arbitrary: has_simp rule: rdistinct.induct)
+  apply simp
+  apply(auto)
+  using add_le_mono rsimp_mono by presburger
+
+lemma larger_acc_smaller_distinct_res0:
+  assumes "ss \<subseteq> SS"
+  shows "rsizes (rdistinct rs SS) \<le> rsizes (rdistinct rs ss)"
+  using assms
+  apply(induct rs arbitrary: ss SS)
+   apply simp
+  by (metis distinct_early_app1 rdistinct_smaller)
+
+lemma without_flts_ineq:
+  shows "rsizes (rdistinct (rflts rs) {}) \<le> rsizes (rdistinct rs {})"
+proof -
+  have "rsizes (rdistinct (rflts rs) {}) \<le>  rsizes (rdistinct rs (insert RZERO {}))"
+    by (metis empty_iff flts_vs_nflts sup_bot_left)
+  also have "... \<le>  rsizes (rdistinct rs {})" 
+    by (simp add: larger_acc_smaller_distinct_res0)
+  finally show ?thesis
+    by blast
+qed
+
+
+lemma distinct_simp_ineq:
+  shows "rsizes (rdistinct (map rsimp rs) {}) \<le> rsizes (rdistinct rs {})"
+  using distinct_simp_ineq_general by blast
+
+
+lemma alts_simp_control:
+  shows "rsize (rsimp (RALTS rs)) \<le> Suc (rsizes (rdistinct rs {}))"
+proof -
+  have "rsize (rsimp (RALTS rs)) \<le> Suc (rsizes (rdistinct (rflts (map rsimp rs)) {}))"
+     using alts_simp_ineq_unfold by auto
+   moreover have "\<dots> \<le> Suc (rsizes (rdistinct (map rsimp rs) {}))"
+    using without_flts_ineq by blast
+  ultimately show "rsize (rsimp (RALTS rs)) \<le> Suc (rsizes (rdistinct rs {}))"
+    by (meson Suc_le_mono distinct_simp_ineq le_trans)
+qed
+
+
+lemma larger_acc_smaller_distinct_res:
+  shows "rsizes (rdistinct rs (insert a ss)) \<le> rsizes (rdistinct rs ss)"
+  by (simp add: larger_acc_smaller_distinct_res0 subset_insertI)
+
+lemma triangle_inequality_distinct:
+  shows "rsizes (rdistinct (a # rs) ss) \<le> rsize a + rsizes (rdistinct rs ss)"
+  apply(case_tac "a \<in> ss")
+   apply simp
+  by (simp add: larger_acc_smaller_distinct_res)
+
+
+lemma distinct_list_size_len_bounded:
+  assumes "\<forall>r \<in> set rs. rsize r \<le> N" "length rs \<le> lrs"
+  shows "rsizes rs \<le> lrs * N "
+  using assms
+  by (metis rlist_bound dual_order.trans mult.commute mult_le_mono1)
+
+
+
+lemma rdistinct_same_set:
+  shows "r \<in> set rs \<longleftrightarrow> r \<in> set (rdistinct rs {})"
+  apply(induct rs)
+   apply simp
+  by (metis rdistinct_set_equality)
+
+(* distinct_list_rexp_up_to_certain_size_bouded_by_set_enumerating_up_to_that_size *)
+lemma distinct_list_rexp_upto:
+  assumes "\<forall>r\<in> set rs. (rsize r) \<le> N"
+  shows "rsizes (rdistinct rs {}) \<le> (card (sizeNregex N)) * N"
+  
+  apply(subgoal_tac "distinct (rdistinct rs {})")
+  prefer 2
+  using rdistinct_does_the_job apply blast
+  apply(subgoal_tac "length (rdistinct rs {}) \<le> card (sizeNregex N)")
+  apply(rule distinct_list_size_len_bounded)
+  using assms
+  apply (meson rdistinct_same_set)
+   apply blast
+  apply(subgoal_tac "\<forall>r \<in> set (rdistinct rs {}). rsize r \<le> N")
+   prefer 2
+  using assms
+   apply (meson rdistinct_same_set)
+  apply(subgoal_tac "length (rdistinct rs {}) = card (set (rdistinct rs {}))")
+   prefer 2
+  apply (simp add: distinct_card)
+  apply(simp)
+  by (metis card_mono finite_size_n mem_Collect_eq sizeNregex_def subsetI)
+
+
+lemma star_control_bounded:
+  assumes "\<forall>s. rsize (rders_simp r s) \<le> N"
+  shows "rsizes (rdistinct (map (\<lambda>s1. RSEQ (rders_simp r s1) (RSTAR r)) (star_updates s r [[c]])) {}) 
+     \<le> (card (sizeNregex (Suc (N + rsize (RSTAR r))))) * (Suc (N + rsize (RSTAR r)))"
+  by (smt (verit) add_Suc_shift add_mono_thms_linordered_semiring(3) assms distinct_list_rexp_upto image_iff list.set_map plus_nat.simps(2) rsize.simps(5))
+
+
+lemma star_closed_form_bounded:
+  assumes "\<forall>s. rsize (rders_simp r s) \<le> N"
+  shows "rsize (rders_simp (RSTAR r) s) \<le> 
+           max ((Suc (card (sizeNregex (Suc (N + rsize (RSTAR r))))) * (Suc (N + rsize (RSTAR r))))) (rsize (RSTAR r))"
+proof(cases s)
+  case Nil
+  then show "rsize (rders_simp (RSTAR r) s)
+    \<le> max (Suc (card (sizeNregex (Suc (N + rsize (RSTAR r))))) * Suc (N + rsize (RSTAR r))) (rsize (RSTAR r))" 
+    by simp
+next
+  case (Cons a list)
+  then have "rsize (rders_simp (RSTAR r) s) = 
+    rsize (rsimp (RALTS ((map (\<lambda>s1. RSEQ (rders_simp r s1) (RSTAR r)) (star_updates list r [[a]])))))"
+    using star_closed_form by fastforce
+  also have "... \<le> Suc (rsizes (rdistinct (map (\<lambda>s1. RSEQ (rders_simp r s1) (RSTAR r)) (star_updates list r [[a]])) {}))"
+    using alts_simp_control by blast 
+  also have "... \<le> Suc (card (sizeNregex (Suc (N + rsize (RSTAR r))))) * (Suc (N + rsize (RSTAR r)))" 
+    using star_control_bounded[OF assms] by (metis add_mono le_add1 mult_Suc plus_1_eq_Suc)
+  also have "... \<le> max (Suc (card (sizeNregex (Suc (N + rsize (RSTAR r))))) * Suc (N + rsize (RSTAR r))) (rsize (RSTAR r))"
+    by simp    
+  finally show ?thesis by simp  
+qed
+
+
+lemma seq_estimate_bounded: 
+  assumes "\<forall>s. rsize (rders_simp r1 s) \<le> N1" 
+      and "\<forall>s. rsize (rders_simp r2 s) \<le> N2"
+  shows
+    "rsizes (rdistinct (RSEQ (rders_simp r1 s) r2 # map (rders_simp r2) (vsuf s r1)) {}) 
+       \<le> (Suc (N1 + (rsize r2)) + (N2 * card (sizeNregex N2)))"
+proof -
+  have a: "rsizes (rdistinct (map (rders_simp r2) (vsuf s r1)) {}) \<le> N2 * card (sizeNregex N2)"
+    by (metis assms(2) distinct_list_rexp_upto ex_map_conv mult.commute)
+
+  have "rsizes (rdistinct (RSEQ (rders_simp r1 s) r2 # map (rders_simp r2) (vsuf s r1)) {}) \<le>
+          rsize (RSEQ (rders_simp r1 s) r2) + rsizes (rdistinct (map (rders_simp r2) (vsuf s r1)) {})"
+    using triangle_inequality_distinct by blast    
+  also have "... \<le> rsize (RSEQ (rders_simp r1 s) r2) + N2 * card (sizeNregex N2)"
+    by (simp add: a)
+  also have "... \<le> Suc (N1 + (rsize r2) + N2 * card (sizeNregex N2))"
+    by (simp add: assms(1))
+  finally show ?thesis
+    by force
+qed    
+
+
+lemma seq_closed_form_bounded2: 
+  assumes "\<forall>s. rsize (rders_simp r1 s) \<le> N1"
+  and     "\<forall>s. rsize (rders_simp r2 s) \<le> N2"
+shows "rsize (rders_simp (RSEQ r1 r2) s) 
+          \<le> max (2 + N1 + (rsize r2) + (N2 * card (sizeNregex N2))) (rsize (RSEQ r1 r2))"
+proof(cases s)
+  case Nil
+  then show "rsize (rders_simp (RSEQ r1 r2) s)
+     \<le> max (2 + N1 + (rsize r2) + (N2 * card (sizeNregex N2))) (rsize (RSEQ r1 r2))" 
+    by simp
+next
+  case (Cons a list)
+  then have "rsize (rders_simp (RSEQ r1 r2) s) = 
+    rsize (rsimp (RALTS ((RSEQ (rders_simp r1 s) r2) # (map (rders_simp r2) (vsuf s r1)))))" 
+    using seq_closed_form_variant by (metis list.distinct(1)) 
+  also have "... \<le> Suc (rsizes (rdistinct (RSEQ (rders_simp r1 s) r2 # map (rders_simp r2) (vsuf s r1)) {}))"
+    using alts_simp_control by blast
+  also have "... \<le> 2 + N1 + (rsize r2) + (N2 * card (sizeNregex N2))"
+  using seq_estimate_bounded[OF assms] by auto
+  ultimately show "rsize (rders_simp (RSEQ r1 r2) s)
+       \<le> max (2 + N1 + (rsize r2) + N2 * card (sizeNregex N2)) (rsize (RSEQ r1 r2))"
+    by auto 
+qed
+
+
+lemma rders_simp_bounded: 
+  shows "\<exists>N. \<forall>s. rsize (rders_simp r s) \<le> N"
+  apply(induct r)
+  apply(rule_tac x = "Suc 0 " in exI)
+  using three_easy_cases0 apply force
+  using three_easy_cases1 apply blast
+  using three_easy_casesC apply blast
+  apply(erule exE)+
+  apply(rule exI)
+  apply(rule allI)
+  apply(rule seq_closed_form_bounded2)
+  apply(assumption)
+  apply(assumption)
+  apply (metis alts_closed_form_bounded size_list_estimation')
+  using star_closed_form_bounded by blast
+
+
+unused_thms
+
+end