diff --git a/thys/Epistemic_Logic/Epistemic_Logic.thy b/thys/Epistemic_Logic/Epistemic_Logic.thy
--- a/thys/Epistemic_Logic/Epistemic_Logic.thy
+++ b/thys/Epistemic_Logic/Epistemic_Logic.thy
@@ -1,1267 +1,1298 @@
 (*
   File:      Epistemic_Logic.thy
   Author:    Asta Halkjær From
 
   This work is a formalization of epistemic logic with countably many agents.
   It includes proofs of soundness and completeness for the axiom system K.
   The completeness proof is based on the textbook "Reasoning About Knowledge"
   by Fagin, Halpern, Moses and Vardi (MIT Press 1995).
   The extensions of system K (T, KB, K4, S4, S5) and their completeness proofs
   are based on the textbook "Modal Logic" by Blackburn, de Rijke and Venema
   (Cambridge University Press 2001).
 *)
 
 theory Epistemic_Logic imports "HOL-Library.Countable" begin
 
 section \<open>Syntax\<close>
 
 type_synonym id = string
 
 datatype 'i fm
   = FF (\<open>\<^bold>\<bottom>\<close>)
   | Pro id
   | Dis \<open>'i fm\<close> \<open>'i fm\<close> (infixr \<open>\<^bold>\<or>\<close> 30)
   | Con \<open>'i fm\<close> \<open>'i fm\<close> (infixr \<open>\<^bold>\<and>\<close> 35)
   | Imp \<open>'i fm\<close> \<open>'i fm\<close> (infixr \<open>\<^bold>\<longrightarrow>\<close> 25)
   | K 'i \<open>'i fm\<close>
 
 abbreviation TT (\<open>\<^bold>\<top>\<close>) where
   \<open>TT \<equiv> \<^bold>\<bottom> \<^bold>\<longrightarrow> \<^bold>\<bottom>\<close>
 
 abbreviation Neg (\<open>\<^bold>\<not> _\<close> [40] 40) where
   \<open>Neg p \<equiv> p \<^bold>\<longrightarrow> \<^bold>\<bottom>\<close>
 
 abbreviation \<open>L i p \<equiv> \<^bold>\<not> K i (\<^bold>\<not> p)\<close>
 
 section \<open>Semantics\<close>
 
 datatype ('i, 'w) kripke =
   Kripke (\<W>: \<open>'w set\<close>) (\<pi>: \<open>'w \<Rightarrow> id \<Rightarrow> bool\<close>) (\<K>: \<open>'i \<Rightarrow> 'w \<Rightarrow> 'w set\<close>)
 
 primrec semantics :: \<open>('i, 'w) kripke \<Rightarrow> 'w \<Rightarrow> 'i fm \<Rightarrow> bool\<close> (\<open>_, _ \<Turnstile> _\<close> [50, 50] 50) where
   \<open>(M, w \<Turnstile> \<^bold>\<bottom>) = False\<close>
 | \<open>(M, w \<Turnstile> Pro x) = \<pi> M w x\<close>
 | \<open>(M, w \<Turnstile> (p \<^bold>\<or> q)) = ((M, w \<Turnstile> p) \<or> (M, w \<Turnstile> q))\<close>
 | \<open>(M, w \<Turnstile> (p \<^bold>\<and> q)) = ((M, w \<Turnstile> p) \<and> (M, w \<Turnstile> q))\<close>
 | \<open>(M, w \<Turnstile> (p \<^bold>\<longrightarrow> q)) = ((M, w \<Turnstile> p) \<longrightarrow> (M, w \<Turnstile> q))\<close>
 | \<open>(M, w \<Turnstile> K i p) = (\<forall>v \<in> \<W> M \<inter> \<K> M i w. M, v \<Turnstile> p)\<close>
 
 section \<open>S5 Axioms\<close>
 
 definition reflexive :: \<open>('i, 'w) kripke \<Rightarrow> bool\<close> where
   \<open>reflexive M \<equiv> \<forall>i. \<forall>w \<in> \<W> M. w \<in> \<K> M i w\<close>
 
 definition symmetric :: \<open>('i, 'w) kripke \<Rightarrow> bool\<close> where
   \<open>symmetric M \<equiv> \<forall>i. \<forall>v \<in> \<W> M. \<forall>w \<in> \<W> M. v \<in> \<K> M i w \<longleftrightarrow> w \<in> \<K> M i v\<close>
 
 definition transitive :: \<open>('i, 'w) kripke \<Rightarrow> bool\<close> where
   \<open>transitive M \<equiv> \<forall>i. \<forall>u \<in> \<W> M. \<forall>v \<in> \<W> M. \<forall>w \<in> \<W> M.
     w \<in> \<K> M i v \<and> u \<in> \<K> M i w \<longrightarrow> u \<in> \<K> M i v\<close>
 
 abbreviation refltrans :: \<open>('i, 'w) kripke \<Rightarrow> bool\<close> where
   \<open>refltrans M \<equiv> reflexive M \<and> transitive M\<close>
 
 abbreviation equivalence :: \<open>('i, 'w) kripke \<Rightarrow> bool\<close> where
   \<open>equivalence M \<equiv> reflexive M \<and> symmetric M \<and> transitive M\<close>
 
 lemma Imp_intro [intro]: \<open>(M, w \<Turnstile> p \<Longrightarrow> M, w \<Turnstile> q) \<Longrightarrow> M, w \<Turnstile> (p \<^bold>\<longrightarrow> q)\<close>
   by simp
 
 theorem distribution: \<open>M, w \<Turnstile> (K i p \<^bold>\<and> K i (p \<^bold>\<longrightarrow> q) \<^bold>\<longrightarrow> K i q)\<close>
 proof
   assume \<open>M, w \<Turnstile> (K i p \<^bold>\<and> K i (p \<^bold>\<longrightarrow> q))\<close>
   then have \<open>M, w \<Turnstile> K i p\<close> \<open>M, w \<Turnstile> K i (p \<^bold>\<longrightarrow> q)\<close>
     by simp_all
   then have \<open>\<forall>v \<in> \<W> M \<inter> \<K> M i w. M, v \<Turnstile> p\<close> \<open>\<forall>v \<in> \<W> M \<inter> \<K> M i w. M, v \<Turnstile> (p \<^bold>\<longrightarrow> q)\<close>
     by simp_all
   then have \<open>\<forall>v \<in> \<W> M \<inter> \<K> M i w. M, v \<Turnstile> q\<close>
     by simp
   then show \<open>M, w \<Turnstile> K i q\<close>
     by simp
 qed
 
 theorem generalization:
   assumes valid: \<open>\<forall>(M :: ('i, 'w) kripke) w. M, w \<Turnstile> p\<close>
   shows \<open>(M :: ('i, 'w) kripke), w \<Turnstile> K i p\<close>
 proof -
   have \<open>\<forall>w' \<in> \<K> M i w. M, w' \<Turnstile> p\<close>
     using valid by blast
   then show \<open>M, w \<Turnstile> K i p\<close>
     by simp
 qed
 
 theorem truth:
   assumes \<open>reflexive M\<close> \<open>w \<in> \<W> M\<close>
   shows \<open>M, w \<Turnstile> (K i p \<^bold>\<longrightarrow> p)\<close>
 proof
   assume \<open>M, w \<Turnstile> K i p\<close>
   then have \<open>\<forall>v \<in> \<W> M \<inter> \<K> M i w. M, v \<Turnstile> p\<close>
     by simp
   moreover have \<open>w \<in> \<K> M i w\<close>
     using \<open>reflexive M\<close> \<open>w \<in> \<W> M\<close> unfolding reflexive_def by blast
   ultimately show \<open>M, w \<Turnstile> p\<close>
     using \<open>w \<in> \<W> M\<close> by simp
 qed
 
 theorem pos_introspection:
   assumes \<open>transitive M\<close> \<open>w \<in> \<W> M\<close>
   shows \<open>M, w \<Turnstile> (K i p \<^bold>\<longrightarrow> K i (K i p))\<close>
 proof
   assume \<open>M, w \<Turnstile> K i p\<close>
   then have \<open>\<forall>v \<in> \<W> M \<inter> \<K> M i w. M, v \<Turnstile> p\<close>
     by simp
   then have \<open>\<forall>v \<in> \<W> M \<inter> \<K> M i w. \<forall>u \<in> \<W> M \<inter> \<K> M i v. M, u \<Turnstile> p\<close>
     using \<open>transitive M\<close> \<open>w \<in> \<W> M\<close> unfolding transitive_def by blast
   then have \<open>\<forall>v \<in> \<W> M \<inter> \<K> M i w. M, v \<Turnstile> K i p\<close>
     by simp
   then show \<open>M, w \<Turnstile> K i (K i p)\<close>
     by simp
 qed
 
 theorem neg_introspection:
   assumes \<open>symmetric M\<close> \<open>transitive M\<close> \<open>w \<in> \<W> M\<close>
   shows \<open>M, w \<Turnstile> (\<^bold>\<not> K i p \<^bold>\<longrightarrow> K i (\<^bold>\<not> K i p))\<close>
 proof
   assume \<open>M, w \<Turnstile> \<^bold>\<not> (K i p)\<close>
   then obtain u where \<open>u \<in> \<K> M i w\<close> \<open>\<not> (M, u \<Turnstile> p)\<close> \<open>u \<in> \<W> M\<close>
     by auto
   moreover have \<open>\<forall>v \<in> \<W> M \<inter> \<K> M i w. u \<in> \<W> M \<inter> \<K> M i v\<close>
     using \<open>u \<in> \<K> M i w\<close> \<open>symmetric M\<close> \<open>transitive M\<close> \<open>u \<in> \<W> M\<close> \<open>w \<in> \<W> M\<close>
     unfolding symmetric_def transitive_def by blast
   ultimately have \<open>\<forall>v \<in> \<W> M \<inter> \<K> M i w. M, v \<Turnstile> \<^bold>\<not> K i p\<close>
     by auto
   then show \<open>M, w \<Turnstile> K i (\<^bold>\<not> K i p)\<close>
     by simp
 qed
 
 section \<open>Normal Modal Logic\<close>
 
 primrec eval :: \<open>(id \<Rightarrow> bool) \<Rightarrow> ('i fm \<Rightarrow> bool) \<Rightarrow> 'i fm \<Rightarrow> bool\<close> where
   \<open>eval _ _ \<^bold>\<bottom> = False\<close>
 | \<open>eval g _ (Pro x) = g x\<close>
 | \<open>eval g h (p \<^bold>\<or> q) = (eval g h p \<or> eval g h q)\<close>
 | \<open>eval g h (p \<^bold>\<and> q) = (eval g h p \<and> eval g h q)\<close>
 | \<open>eval g h (p \<^bold>\<longrightarrow> q) = (eval g h p \<longrightarrow> eval g h q)\<close>
 | \<open>eval _ h (K i p) = h (K i p)\<close>
 
 abbreviation \<open>tautology p \<equiv> \<forall>g h. eval g h p\<close>
 
 inductive AK :: \<open>('i fm \<Rightarrow> bool) \<Rightarrow> 'i fm \<Rightarrow> bool\<close> (\<open>_ \<turnstile> _\<close> [20, 20] 20)
   for A :: \<open>'i fm \<Rightarrow> bool\<close> where
     A1: \<open>tautology p \<Longrightarrow> A \<turnstile> p\<close>
   | A2: \<open>A \<turnstile> K i p \<^bold>\<and> K i (p \<^bold>\<longrightarrow> q) \<^bold>\<longrightarrow> K i q\<close>
   | Ax: \<open>A p \<Longrightarrow> A \<turnstile> p\<close>
   | R1: \<open>A \<turnstile> p \<Longrightarrow> A \<turnstile> p \<^bold>\<longrightarrow> q \<Longrightarrow> A \<turnstile> q\<close>
   | R2: \<open>A \<turnstile> p \<Longrightarrow> A \<turnstile> K i p\<close>
 
 section \<open>Soundness\<close>
 
 lemma eval_semantics: \<open>eval (pi w) (\<lambda>q. Kripke W pi r, w \<Turnstile> q) p = (Kripke W pi r, w \<Turnstile> p)\<close>
   by (induct p) simp_all
 
 lemma tautology:
   assumes \<open>tautology p\<close>
   shows \<open>M, w \<Turnstile> p\<close>
 proof -
   from assms have \<open>eval (g w) (\<lambda>q. Kripke W g r, w \<Turnstile> q) p\<close> for W g r
     by simp
   then have \<open>Kripke W g r, w \<Turnstile> p\<close> for W g r
     using eval_semantics by fast
   then show \<open>M, w \<Turnstile> p\<close>
     by (metis kripke.collapse)
 qed
 
 theorem soundness:
-  fixes M :: \<open>('i, 'w) kripke\<close>
-  assumes \<open>\<And>(M :: ('i, 'w) kripke) w p. A p \<Longrightarrow> P M \<Longrightarrow> w \<in> \<W> M \<Longrightarrow> M, w \<Turnstile> p\<close>
+  fixes P :: \<open>('i, 'w) kripke \<Rightarrow> bool\<close>
+  assumes \<open>\<And>M w p. A p \<Longrightarrow> P M \<Longrightarrow> w \<in> \<W> M \<Longrightarrow> M, w \<Turnstile> p\<close>
   shows \<open>A \<turnstile> p \<Longrightarrow> P M \<Longrightarrow> w \<in> \<W> M \<Longrightarrow> M, w \<Turnstile> p\<close>
   by (induct p arbitrary: w rule: AK.induct) (auto simp: assms tautology)
 
 section \<open>Derived rules\<close>
 
 lemma K_A2': \<open>A \<turnstile> K i (p \<^bold>\<longrightarrow> q) \<^bold>\<longrightarrow> K i p \<^bold>\<longrightarrow> K i q\<close>
 proof -
   have \<open>A \<turnstile> K i p \<^bold>\<and> K i (p \<^bold>\<longrightarrow> q) \<^bold>\<longrightarrow> K i q\<close>
     using A2 by fast
   moreover have \<open>A \<turnstile> (P \<^bold>\<and> Q \<^bold>\<longrightarrow> R) \<^bold>\<longrightarrow> (Q \<^bold>\<longrightarrow> P \<^bold>\<longrightarrow> R)\<close> for P Q R
     by (simp add: A1)
   ultimately show ?thesis
     using R1 by fast
 qed
 
 lemma K_map:
   assumes \<open>A \<turnstile> p \<^bold>\<longrightarrow> q\<close>
   shows \<open>A \<turnstile> K i p \<^bold>\<longrightarrow> K i q\<close>
 proof -
   note \<open>A \<turnstile> p \<^bold>\<longrightarrow> q\<close>
   then have \<open>A \<turnstile> K i (p \<^bold>\<longrightarrow> q)\<close>
     using R2 by fast
   moreover have \<open>A \<turnstile> K i (p \<^bold>\<longrightarrow> q) \<^bold>\<longrightarrow> K i p \<^bold>\<longrightarrow> K i q\<close>
     using K_A2' by fast
   ultimately show ?thesis
     using R1 by fast
 qed
 
 lemma K_LK: \<open>A \<turnstile> (L i (\<^bold>\<not> p) \<^bold>\<longrightarrow> \<^bold>\<not> K i p)\<close>
 proof -
   have \<open>A \<turnstile> (p \<^bold>\<longrightarrow> \<^bold>\<not> \<^bold>\<not> p)\<close>
     by (simp add: A1)
   moreover have \<open>A \<turnstile> ((P \<^bold>\<longrightarrow> Q) \<^bold>\<longrightarrow> (\<^bold>\<not> Q \<^bold>\<longrightarrow> \<^bold>\<not> P))\<close> for P Q
     using A1 by force
   ultimately show ?thesis
     using K_map R1 by fast
 qed
 
 primrec imply :: \<open>'i fm list \<Rightarrow> 'i fm \<Rightarrow> 'i fm\<close> (infixr \<open>\<^bold>\<leadsto>\<close> 26) where
-  \<open>imply [] q = q\<close>
-| \<open>imply (p # ps) q = (p \<^bold>\<longrightarrow> ps \<^bold>\<leadsto> q)\<close>
+  \<open>([] \<^bold>\<leadsto> q) = q\<close>
+| \<open>(p # ps \<^bold>\<leadsto> q) = (p \<^bold>\<longrightarrow> ps \<^bold>\<leadsto> q)\<close>
 
 lemma K_imply_head: \<open>A \<turnstile> (p # ps \<^bold>\<leadsto> p)\<close>
 proof -
   have \<open>tautology (p # ps \<^bold>\<leadsto> p)\<close>
     by (induct ps) simp_all
   then show ?thesis
     using A1 by blast
 qed
 
 lemma K_imply_Cons:
   assumes \<open>A \<turnstile> ps \<^bold>\<leadsto> q\<close>
   shows \<open>A \<turnstile> p # ps \<^bold>\<leadsto> q\<close>
 proof -
   have \<open>A \<turnstile> (ps \<^bold>\<leadsto> q \<^bold>\<longrightarrow> p # ps \<^bold>\<leadsto> q)\<close>
     by (simp add: A1)
   with R1 assms show ?thesis .
 qed
 
 lemma K_right_mp:
   assumes \<open>A \<turnstile> ps \<^bold>\<leadsto> p\<close> \<open>A \<turnstile> ps \<^bold>\<leadsto> (p \<^bold>\<longrightarrow> q)\<close>
   shows \<open>A \<turnstile> ps \<^bold>\<leadsto> q\<close>
 proof -
   have \<open>tautology (ps \<^bold>\<leadsto> p \<^bold>\<longrightarrow> ps \<^bold>\<leadsto> (p \<^bold>\<longrightarrow> q) \<^bold>\<longrightarrow> ps \<^bold>\<leadsto> q)\<close>
     by (induct ps) simp_all
   with A1 have \<open>A \<turnstile> ps \<^bold>\<leadsto> p \<^bold>\<longrightarrow> ps \<^bold>\<leadsto> (p \<^bold>\<longrightarrow> q) \<^bold>\<longrightarrow> ps \<^bold>\<leadsto> q\<close> .
   then show ?thesis
     using assms R1 by blast
 qed
 
 lemma tautology_imply_superset:
   assumes \<open>set ps \<subseteq> set qs\<close>
   shows \<open>tautology (ps \<^bold>\<leadsto> r \<^bold>\<longrightarrow> qs \<^bold>\<leadsto> r)\<close>
 proof (rule ccontr)
   assume \<open>\<not> tautology (ps \<^bold>\<leadsto> r \<^bold>\<longrightarrow> qs \<^bold>\<leadsto> r)\<close>
   then obtain g h where \<open>\<not> eval g h (ps \<^bold>\<leadsto> r \<^bold>\<longrightarrow> qs \<^bold>\<leadsto> r)\<close>
     by blast
   then have \<open>eval g h (ps \<^bold>\<leadsto> r)\<close> \<open>\<not> eval g h (qs \<^bold>\<leadsto> r)\<close>
     by simp_all
   then consider (np) \<open>\<exists>p \<in> set ps. \<not> eval g h p\<close> | (r) \<open>\<forall>p \<in> set ps. eval g h p\<close> \<open>eval g h r\<close>
     by (induct ps) auto
   then show False
   proof cases
     case np
     then have \<open>\<exists>p \<in> set qs. \<not> eval g h p\<close>
       using \<open>set ps \<subseteq> set qs\<close> by blast
     then have \<open>eval g h (qs \<^bold>\<leadsto> r)\<close>
       by (induct qs) simp_all
     then show ?thesis
       using \<open>\<not> eval g h (qs \<^bold>\<leadsto> r)\<close> by blast
   next
     case r
     then have \<open>eval g h (qs \<^bold>\<leadsto> r)\<close>
       by (induct qs) simp_all
     then show ?thesis
       using \<open>\<not> eval g h (qs \<^bold>\<leadsto> r)\<close> by blast
   qed
 qed
 
 lemma K_imply_weaken:
   assumes \<open>A \<turnstile> ps \<^bold>\<leadsto> q\<close> \<open>set ps \<subseteq> set ps'\<close>
   shows \<open>A \<turnstile> ps' \<^bold>\<leadsto> q\<close>
 proof -
   have \<open>tautology (ps \<^bold>\<leadsto> q \<^bold>\<longrightarrow> ps' \<^bold>\<leadsto> q)\<close>
     using \<open>set ps \<subseteq> set ps'\<close> tautology_imply_superset by blast
   then have \<open>A \<turnstile> (ps \<^bold>\<leadsto> q \<^bold>\<longrightarrow> ps' \<^bold>\<leadsto> q)\<close>
     using A1 by blast
   then show ?thesis
     using \<open>A \<turnstile> ps \<^bold>\<leadsto> q\<close> R1 by blast
 qed
 
 lemma imply_append: \<open>(ps @ ps' \<^bold>\<leadsto> q) = (ps \<^bold>\<leadsto> ps' \<^bold>\<leadsto> q)\<close>
   by (induct ps) simp_all
 
 lemma K_ImpI:
   assumes \<open>A \<turnstile> p # G \<^bold>\<leadsto> q\<close>
   shows \<open>A \<turnstile> G \<^bold>\<leadsto> (p \<^bold>\<longrightarrow> q)\<close>
 proof -
   have \<open>set (p # G) \<subseteq> set (G @ [p])\<close>
     by simp
   then have \<open>A \<turnstile> G @ [p] \<^bold>\<leadsto> q\<close>
     using assms K_imply_weaken by blast
   then have \<open>A \<turnstile> G \<^bold>\<leadsto> [p] \<^bold>\<leadsto> q\<close>
     using imply_append by metis
   then show ?thesis
     by simp
 qed
 
 lemma K_Boole:
   assumes \<open>A \<turnstile> (\<^bold>\<not> p) # G \<^bold>\<leadsto> \<^bold>\<bottom>\<close>
   shows \<open>A \<turnstile> G \<^bold>\<leadsto> p\<close>
 proof -
   have \<open>A \<turnstile> G \<^bold>\<leadsto> \<^bold>\<not> \<^bold>\<not> p\<close>
     using assms K_ImpI by blast
   moreover have \<open>tautology (G \<^bold>\<leadsto> \<^bold>\<not> \<^bold>\<not> p \<^bold>\<longrightarrow> G \<^bold>\<leadsto> p)\<close>
     by (induct G) simp_all
   then have \<open>A \<turnstile> (G \<^bold>\<leadsto> \<^bold>\<not> \<^bold>\<not> p \<^bold>\<longrightarrow> G \<^bold>\<leadsto> p)\<close>
     using A1 by blast
   ultimately show ?thesis
     using R1 by blast
 qed
 
 lemma K_DisE:
   assumes \<open>A \<turnstile> p # G \<^bold>\<leadsto> r\<close> \<open>A \<turnstile> q # G \<^bold>\<leadsto> r\<close> \<open>A \<turnstile> G \<^bold>\<leadsto> p \<^bold>\<or> q\<close>
   shows \<open>A \<turnstile> G \<^bold>\<leadsto> r\<close>
 proof -
   have \<open>tautology (p # G \<^bold>\<leadsto> r \<^bold>\<longrightarrow> q # G \<^bold>\<leadsto> r \<^bold>\<longrightarrow> G \<^bold>\<leadsto> p \<^bold>\<or> q \<^bold>\<longrightarrow> G \<^bold>\<leadsto> r)\<close>
     by (induct G) auto
   then have \<open>A \<turnstile> p # G \<^bold>\<leadsto> r \<^bold>\<longrightarrow> q # G \<^bold>\<leadsto> r \<^bold>\<longrightarrow> G \<^bold>\<leadsto> p \<^bold>\<or> q \<^bold>\<longrightarrow> G \<^bold>\<leadsto> r\<close>
     using A1 by blast
   then show ?thesis
     using assms R1 by blast
 qed
 
 lemma K_mp: \<open>A \<turnstile> p # (p \<^bold>\<longrightarrow> q) # G \<^bold>\<leadsto> q\<close>
   by (meson K_imply_head K_imply_weaken K_right_mp set_subset_Cons)
 
 lemma K_swap:
   assumes \<open>A \<turnstile> p # q # G \<^bold>\<leadsto> r\<close>
   shows \<open>A \<turnstile> q # p # G \<^bold>\<leadsto> r\<close>
   using assms K_ImpI by (metis imply.simps(1-2))
 
 lemma K_DisL:
   assumes \<open>A \<turnstile> p # ps \<^bold>\<leadsto> q\<close> \<open>A \<turnstile> p' # ps \<^bold>\<leadsto> q\<close>
   shows \<open>A \<turnstile> (p \<^bold>\<or> p') # ps \<^bold>\<leadsto> q\<close>
 proof -
   have \<open>A \<turnstile> p # (p \<^bold>\<or> p') # ps \<^bold>\<leadsto> q\<close> \<open>A \<turnstile> p' # (p \<^bold>\<or> p') # ps \<^bold>\<leadsto> q\<close>
     using assms K_swap K_imply_Cons by blast+
   moreover have \<open>A \<turnstile> (p \<^bold>\<or> p') # ps \<^bold>\<leadsto> p \<^bold>\<or> p'\<close>
     using K_imply_head by blast
   ultimately show ?thesis
     using K_DisE by blast
 qed
 
 lemma K_distrib_K_imp:
   assumes \<open>A \<turnstile> K i (G \<^bold>\<leadsto> q)\<close>
   shows \<open>A \<turnstile> map (K i) G \<^bold>\<leadsto> K i q\<close>
 proof -
   have \<open>A \<turnstile> (K i (G \<^bold>\<leadsto> q) \<^bold>\<longrightarrow> map (K i) G \<^bold>\<leadsto> K i q)\<close>
   proof (induct G)
     case Nil
     then show ?case
       by (simp add: A1)
   next
     case (Cons a G)
     have \<open>A \<turnstile> K i a \<^bold>\<and> K i (a # G \<^bold>\<leadsto> q) \<^bold>\<longrightarrow> K i (G \<^bold>\<leadsto> q)\<close>
       by (simp add: A2)
     moreover have
       \<open>A \<turnstile> ((K i a \<^bold>\<and> K i (a # G \<^bold>\<leadsto> q) \<^bold>\<longrightarrow> K i (G \<^bold>\<leadsto> q)) \<^bold>\<longrightarrow>
         (K i (G \<^bold>\<leadsto> q) \<^bold>\<longrightarrow> map (K i) G \<^bold>\<leadsto> K i q) \<^bold>\<longrightarrow>
         (K i a \<^bold>\<and> K i (a # G \<^bold>\<leadsto> q) \<^bold>\<longrightarrow> map (K i) G \<^bold>\<leadsto> K i q))\<close>
       by (simp add: A1)
     ultimately have \<open>A \<turnstile> K i a \<^bold>\<and> K i (a # G \<^bold>\<leadsto> q) \<^bold>\<longrightarrow> map (K i) G \<^bold>\<leadsto> K i q\<close>
       using Cons R1 by blast
     moreover have
       \<open>A \<turnstile> ((K i a \<^bold>\<and> K i (a # G \<^bold>\<leadsto> q) \<^bold>\<longrightarrow> map (K i) G \<^bold>\<leadsto> K i q) \<^bold>\<longrightarrow>
         (K i (a # G \<^bold>\<leadsto> q) \<^bold>\<longrightarrow> K i a \<^bold>\<longrightarrow> map (K i) G \<^bold>\<leadsto> K i q))\<close>
       by (simp add: A1)
     ultimately have \<open>A \<turnstile> (K i (a # G \<^bold>\<leadsto> q) \<^bold>\<longrightarrow> K i a \<^bold>\<longrightarrow> map (K i) G \<^bold>\<leadsto> K i q)\<close>
       using R1 by blast
     then show ?case
       by simp
   qed
   then show ?thesis
     using assms R1 by blast
 qed
 
 section \<open>Completeness\<close>
 
 subsection \<open>Consistent sets\<close>
 
 definition consistent :: \<open>('i fm \<Rightarrow> bool) \<Rightarrow> 'i fm set \<Rightarrow> bool\<close> where
   \<open>consistent A S \<equiv> \<nexists>S'. set S' \<subseteq> S \<and> (A \<turnstile> S' \<^bold>\<leadsto> \<^bold>\<bottom>)\<close>
 
 lemma inconsistent_subset:
   assumes \<open>consistent A V\<close> \<open>\<not> consistent A ({p} \<union> V)\<close>
   obtains V' where \<open>set V' \<subseteq> V\<close> \<open>A \<turnstile> p # V' \<^bold>\<leadsto> \<^bold>\<bottom>\<close>
 proof -
   obtain V' where V': \<open>set V' \<subseteq> ({p} \<union> V)\<close> \<open>p \<in> set V'\<close> \<open>A \<turnstile> V' \<^bold>\<leadsto> \<^bold>\<bottom>\<close>
     using assms unfolding consistent_def by blast
   then have *: \<open>A \<turnstile> p # V' \<^bold>\<leadsto> \<^bold>\<bottom>\<close>
     using K_imply_Cons by blast
 
   let ?S = \<open>removeAll p V'\<close>
   have \<open>set (p # V') \<subseteq> set (p # ?S)\<close>
     by auto
   then have \<open>A \<turnstile> p # ?S \<^bold>\<leadsto> \<^bold>\<bottom>\<close>
     using * K_imply_weaken by blast
   moreover have \<open>set ?S \<subseteq> V\<close>
     using V'(1) by (metis Diff_subset_conv set_removeAll)
   ultimately show ?thesis
     using that by blast
 qed
 
 lemma consistent_consequent:
   assumes \<open>consistent A V\<close> \<open>p \<in> V\<close> \<open>A \<turnstile> p \<^bold>\<longrightarrow> q\<close>
   shows \<open>consistent A ({q} \<union> V)\<close>
 proof -
   have \<open>\<forall>V'. set V' \<subseteq> V \<longrightarrow> \<not> (A \<turnstile> p # V' \<^bold>\<leadsto> \<^bold>\<bottom>)\<close>
     using \<open>consistent A V\<close> \<open>p \<in> V\<close> unfolding consistent_def
     by (metis insert_subset list.simps(15))
   then have \<open>\<forall>V'. set V' \<subseteq> V \<longrightarrow> \<not> (A \<turnstile> q # V' \<^bold>\<leadsto> \<^bold>\<bottom>)\<close>
     using \<open>A \<turnstile> (p \<^bold>\<longrightarrow> q)\<close> K_imply_head K_right_mp by (metis imply.simps(1-2))
   then show ?thesis
     using \<open>consistent A V\<close> inconsistent_subset by metis
 qed
 
 lemma consistent_consequent':
   assumes \<open>consistent A V\<close> \<open>p \<in> V\<close> \<open>tautology (p \<^bold>\<longrightarrow> q)\<close>
   shows \<open>consistent A ({q} \<union> V)\<close>
   using assms consistent_consequent A1 by blast
 
 lemma consistent_disjuncts:
   assumes \<open>consistent A V\<close> \<open>(p \<^bold>\<or> q) \<in> V\<close>
   shows \<open>consistent A ({p} \<union> V) \<or> consistent A ({q} \<union> V)\<close>
 proof (rule ccontr)
   assume \<open>\<not> ?thesis\<close>
   then have \<open>\<not> consistent A ({p} \<union> V)\<close> \<open>\<not> consistent A ({q} \<union> V)\<close>
     by blast+
 
   then obtain S' T' where
     S': \<open>set S' \<subseteq> V\<close> \<open>A \<turnstile> p # S' \<^bold>\<leadsto> \<^bold>\<bottom>\<close> and
     T': \<open>set T' \<subseteq> V\<close> \<open>A \<turnstile> q # T' \<^bold>\<leadsto> \<^bold>\<bottom>\<close>
     using \<open>consistent A V\<close> inconsistent_subset by metis
 
   from S' have p: \<open>A \<turnstile> p # S' @ T' \<^bold>\<leadsto> \<^bold>\<bottom>\<close>
     by (metis K_imply_weaken Un_upper1 append_Cons set_append)
   moreover from T' have q: \<open>A \<turnstile> q # S' @ T' \<^bold>\<leadsto> \<^bold>\<bottom>\<close>
     by (metis K_imply_head K_right_mp R1 imply.simps(2) imply_append)
   ultimately have \<open>A \<turnstile> (p \<^bold>\<or> q) # S' @ T' \<^bold>\<leadsto> \<^bold>\<bottom>\<close>
     using K_DisL by blast
   then have \<open>A \<turnstile> S' @ T' \<^bold>\<leadsto> \<^bold>\<bottom>\<close>
     using S'(1) T'(1) p q \<open>consistent A V\<close> \<open>(p \<^bold>\<or> q) \<in> V\<close> unfolding consistent_def
     by (metis Un_subset_iff insert_subset list.simps(15) set_append)
   moreover have \<open>set (S' @ T') \<subseteq> V\<close>
     by (simp add: S'(1) T'(1))
   ultimately show False
     using \<open>consistent A V\<close> unfolding consistent_def by blast
 qed
 
 lemma exists_finite_inconsistent:
   assumes \<open>\<not> consistent A ({\<^bold>\<not> p} \<union> V)\<close>
   obtains W where \<open>{\<^bold>\<not> p} \<union> W \<subseteq> {\<^bold>\<not> p} \<union> V\<close> \<open>(\<^bold>\<not> p) \<notin> W\<close> \<open>finite W\<close> \<open>\<not> consistent A ({\<^bold>\<not> p} \<union> W)\<close>
 proof -
   obtain W' where W': \<open>set W' \<subseteq> {\<^bold>\<not> p} \<union> V\<close> \<open>A \<turnstile> W' \<^bold>\<leadsto> \<^bold>\<bottom>\<close>
     using assms unfolding consistent_def by blast
   let ?S = \<open>removeAll (\<^bold>\<not> p) W'\<close>
   have \<open>\<not> consistent A ({\<^bold>\<not> p} \<union> set ?S)\<close>
     unfolding consistent_def using W'(2) by auto
   moreover have \<open>finite (set ?S)\<close>
     by blast
   moreover have \<open>{\<^bold>\<not> p} \<union> set ?S \<subseteq> {\<^bold>\<not> p} \<union> V\<close>
     using W'(1) by auto
   moreover have \<open>(\<^bold>\<not> p) \<notin> set ?S\<close>
     by simp
   ultimately show ?thesis
     by (meson that)
 qed
 
 lemma inconsistent_imply:
   assumes \<open>\<not> consistent A ({\<^bold>\<not> p} \<union> set G)\<close>
   shows \<open>A \<turnstile> G \<^bold>\<leadsto> p\<close>
   using assms K_Boole K_imply_weaken unfolding consistent_def
   by (metis insert_is_Un list.simps(15))
 
 subsection \<open>Maximal consistent sets\<close>
 
 definition maximal :: \<open>('i fm \<Rightarrow> bool) \<Rightarrow> 'i fm set \<Rightarrow> bool\<close> where
   \<open>maximal A S \<equiv> \<forall>p. p \<notin> S \<longrightarrow> \<not> consistent A ({p} \<union> S)\<close>
 
 theorem deriv_in_maximal:
   assumes \<open>consistent A V\<close> \<open>maximal A V\<close> \<open>A \<turnstile> p\<close>
   shows \<open>p \<in> V\<close>
   using assms R1 inconsistent_subset unfolding consistent_def maximal_def
   by (metis imply.simps(2))
 
 theorem exactly_one_in_maximal:
   assumes \<open>consistent A V\<close> \<open>maximal A V\<close>
   shows \<open>p \<in> V \<longleftrightarrow> (\<^bold>\<not> p) \<notin> V\<close>
 proof
   assume \<open>p \<in> V\<close>
   then show \<open>(\<^bold>\<not> p) \<notin> V\<close>
     using assms K_mp unfolding consistent_def maximal_def
     by (metis empty_subsetI insert_subset list.set(1) list.simps(15))
 next
   assume \<open>(\<^bold>\<not> p) \<notin> V\<close>
   have \<open>A \<turnstile> (p \<^bold>\<or> \<^bold>\<not> p)\<close>
     by (simp add: A1)
   then have \<open>(p \<^bold>\<or> \<^bold>\<not> p) \<in> V\<close>
     using assms deriv_in_maximal by blast
   then have \<open>consistent A ({p} \<union> V) \<or> consistent A ({\<^bold>\<not> p} \<union> V)\<close>
     using assms consistent_disjuncts by blast
   then show \<open>p \<in> V\<close>
     using \<open>maximal A V\<close> \<open>(\<^bold>\<not> p) \<notin> V\<close> unfolding maximal_def by blast
 qed
 
 theorem consequent_in_maximal:
   assumes \<open>consistent A V\<close> \<open>maximal A V\<close> \<open>p \<in> V\<close> \<open>(p \<^bold>\<longrightarrow> q) \<in> V\<close>
   shows \<open>q \<in> V\<close>
 proof -
   have \<open>\<forall>V'. set V' \<subseteq> V \<longrightarrow> \<not> (A \<turnstile> p # (p \<^bold>\<longrightarrow> q) # V' \<^bold>\<leadsto> \<^bold>\<bottom>)\<close>
     using \<open>consistent A V\<close> \<open>p \<in> V\<close> \<open>(p \<^bold>\<longrightarrow> q) \<in> V\<close> unfolding consistent_def
     by (metis insert_subset list.simps(15))
   then have \<open>\<forall>V'. set V' \<subseteq> V \<longrightarrow> \<not> (A \<turnstile> q # V' \<^bold>\<leadsto> \<^bold>\<bottom>)\<close>
     by (meson K_mp K_ImpI K_imply_weaken K_right_mp set_subset_Cons)
   then have \<open>consistent A ({q} \<union> V)\<close>
     using \<open>consistent A V\<close> inconsistent_subset by metis
   then show ?thesis
     using \<open>maximal A V\<close> unfolding maximal_def by fast
 qed
 
 theorem ax_in_maximal:
   assumes \<open>consistent A V\<close> \<open>maximal A V\<close> \<open>A p\<close>
   shows \<open>p \<in> V\<close>
   using assms deriv_in_maximal Ax by blast
 
 theorem mcs_properties:
   assumes \<open>consistent A V\<close> and \<open>maximal A V\<close>
   shows \<open>A \<turnstile> p \<Longrightarrow> p \<in> V\<close>
     and \<open>p \<in> V \<longleftrightarrow> (\<^bold>\<not> p) \<notin> V\<close>
     and \<open>p \<in> V \<Longrightarrow> (p \<^bold>\<longrightarrow> q) \<in> V \<Longrightarrow> q \<in> V\<close>
   using assms deriv_in_maximal exactly_one_in_maximal consequent_in_maximal by blast+
 
 subsection \<open>Lindenbaum extension\<close>
 
 instantiation fm :: (countable) countable begin
 instance by countable_datatype
 end
 
 primrec extend :: \<open>('i fm \<Rightarrow> bool) \<Rightarrow> 'i fm set \<Rightarrow> (nat \<Rightarrow> 'i fm) \<Rightarrow> nat \<Rightarrow> 'i fm set\<close> where
   \<open>extend A S f 0 = S\<close>
 | \<open>extend A S f (Suc n) =
     (if consistent A ({f n} \<union> extend A S f n)
      then {f n} \<union> extend A S f n
      else extend A S f n)\<close>
 
 definition Extend :: \<open>('i fm \<Rightarrow> bool) \<Rightarrow> 'i fm set \<Rightarrow> (nat \<Rightarrow> 'i fm) \<Rightarrow> 'i fm set\<close> where
   \<open>Extend A S f \<equiv> \<Union>n. extend A S f n\<close>
 
 lemma Extend_subset: \<open>S \<subseteq> Extend A S f\<close>
   unfolding Extend_def using Union_upper extend.simps(1) range_eqI
   by metis
 
 lemma extend_bound: \<open>(\<Union>n \<le> m. extend A S f n) = extend A S f m\<close>
   by (induct m) (simp_all add: atMost_Suc)
 
 lemma consistent_extend: \<open>consistent A S \<Longrightarrow> consistent A (extend A S f n)\<close>
   by (induct n) simp_all
 
 lemma UN_finite_bound:
   assumes \<open>finite A\<close> \<open>A \<subseteq> (\<Union>n. f n)\<close>
   shows \<open>\<exists>m :: nat. A \<subseteq> (\<Union>n \<le> m. f n)\<close>
   using assms
 proof (induct rule: finite_induct)
   case (insert x A)
   then obtain m where \<open>A \<subseteq> (\<Union>n \<le> m. f n)\<close>
     by fast
   then have \<open>A \<subseteq> (\<Union>n \<le> (m + k). f n)\<close> for k
     by fastforce
   moreover obtain m' where \<open>x \<in> f m'\<close>
     using insert(4) by blast
   ultimately have \<open>{x} \<union> A \<subseteq> (\<Union>n \<le> m + m'. f n)\<close>
     by auto
   then show ?case
     by blast
 qed simp
 
 lemma consistent_Extend:
   assumes \<open>consistent A S\<close>
   shows \<open>consistent A (Extend A S f)\<close>
   unfolding Extend_def
 proof (rule ccontr)
   assume \<open>\<not> consistent A (\<Union>n. extend A S f n)\<close>
   then obtain S' where \<open>A \<turnstile> S' \<^bold>\<leadsto> \<^bold>\<bottom>\<close> \<open>set S' \<subseteq> (\<Union>n. extend A S f n)\<close>
     unfolding consistent_def by blast
   then obtain m where \<open>set S' \<subseteq> (\<Union>n \<le> m. extend A S f n)\<close>
     using UN_finite_bound by (metis List.finite_set)
   then have \<open>set S' \<subseteq> extend A S f m\<close>
     using extend_bound by blast
   moreover have \<open>consistent A (extend A S f m)\<close>
     using assms consistent_extend by blast
   ultimately show False
     unfolding consistent_def using \<open>A \<turnstile> S' \<^bold>\<leadsto> \<^bold>\<bottom>\<close> by blast
 qed
 
 lemma maximal_Extend:
   assumes \<open>surj f\<close>
   shows \<open>maximal A (Extend A S f)\<close>
 proof (rule ccontr)
   assume \<open>\<not> maximal A (Extend A S f)\<close>
   then obtain p where \<open>p \<notin> Extend A S f\<close> \<open>consistent A ({p} \<union> Extend A S f)\<close>
     unfolding maximal_def using assms consistent_Extend by blast
   obtain k where n: \<open>f k = p\<close>
     using \<open>surj f\<close> unfolding surj_def by metis
   then have \<open>p \<notin> extend A S f (Suc k)\<close>
     using \<open>p \<notin> Extend A S f\<close> unfolding Extend_def by blast
   then have \<open>\<not> consistent A ({p} \<union> extend A S f k)\<close>
     using n by fastforce
   moreover have \<open>{p} \<union> extend A S f k \<subseteq> {p} \<union> Extend A S f\<close>
     unfolding Extend_def by blast
   ultimately have \<open>\<not> consistent A ({p} \<union> Extend A S f)\<close>
     unfolding consistent_def by fastforce
   then show False
     using \<open>consistent A ({p} \<union> Extend A S f)\<close> by blast
 qed
 
 lemma maximal_extension:
   fixes V :: \<open>('i :: countable) fm set\<close>
   assumes \<open>consistent A V\<close>
   obtains W where \<open>V \<subseteq> W\<close> \<open>consistent A W\<close> \<open>maximal A W\<close>
 proof -
   let ?W = \<open>Extend A V from_nat\<close>
   have \<open>V \<subseteq> ?W\<close>
     using Extend_subset by blast
   moreover have \<open>consistent A ?W\<close>
     using assms consistent_Extend by blast
   moreover have \<open>maximal A ?W\<close>
     using assms maximal_Extend surj_from_nat by blast
   ultimately show ?thesis
     using that by blast
 qed
 
 subsection \<open>Canonical model\<close>
 
 abbreviation pi :: \<open>'i fm set \<Rightarrow> id \<Rightarrow> bool\<close> where
   \<open>pi V x \<equiv> Pro x \<in> V\<close>
 
 abbreviation known :: \<open>'i fm set \<Rightarrow> 'i \<Rightarrow> 'i fm set\<close> where
   \<open>known V i \<equiv> {p. K i p \<in> V}\<close>
 
 abbreviation reach :: \<open>('i fm \<Rightarrow> bool) \<Rightarrow> 'i \<Rightarrow> 'i fm set \<Rightarrow> 'i fm set set\<close> where
   \<open>reach A i V \<equiv> {W. known V i \<subseteq> W}\<close>
 
 abbreviation mcss :: \<open>('i fm \<Rightarrow> bool) \<Rightarrow> 'i fm set set\<close> where
   \<open>mcss A \<equiv> {W. consistent A W \<and> maximal A W}\<close>
 
 abbreviation canonical :: \<open>('i fm \<Rightarrow> bool) \<Rightarrow> ('i, 'i fm set) kripke\<close> where
   \<open>canonical A \<equiv> Kripke (mcss A) pi (reach A)\<close>
 
 lemma truth_lemma:
   fixes A and p :: \<open>('i :: countable) fm\<close>
-  defines \<open>M \<equiv> canonical A\<close>
   assumes \<open>consistent A V\<close> and \<open>maximal A V\<close>
-  shows \<open>p \<in> V \<longleftrightarrow> M, V \<Turnstile> p\<close>
-  using assms unfolding M_def
+  shows \<open>p \<in> V \<longleftrightarrow> canonical A, V \<Turnstile> p\<close>
+  using assms
 proof (induct p arbitrary: V)
   case FF
   then show ?case
   proof safe
     assume \<open>\<^bold>\<bottom> \<in> V\<close>
     then have False
       using \<open>consistent A V\<close> K_imply_head unfolding consistent_def
       by (metis bot.extremum insert_subset list.set(1) list.simps(15))
     then show \<open>canonical A, V \<Turnstile> \<^bold>\<bottom>\<close> ..
   next
     assume \<open>canonical A, V \<Turnstile> \<^bold>\<bottom>\<close>
     then show \<open>\<^bold>\<bottom> \<in> V\<close>
       by simp
   qed
 next
   case (Pro x)
   then show ?case
     by simp
 next
   case (Dis p q)
   then show ?case
   proof safe
     assume \<open>(p \<^bold>\<or> q) \<in> V\<close>
     then have \<open>consistent A ({p} \<union> V) \<or> consistent A ({q} \<union> V)\<close>
       using \<open>consistent A V\<close> consistent_disjuncts by blast
     then have \<open>p \<in> V \<or> q \<in> V\<close>
       using \<open>maximal A V\<close> unfolding maximal_def by fast
     then show \<open>canonical A, V \<Turnstile> (p \<^bold>\<or> q)\<close>
       using Dis by simp
   next
     assume \<open>canonical A, V \<Turnstile> (p \<^bold>\<or> q)\<close>
     then consider \<open>canonical A, V \<Turnstile> p\<close> | \<open>canonical A, V \<Turnstile> q\<close>
       by auto
     then have \<open>p \<in> V \<or> q \<in> V\<close>
       using Dis by auto
     moreover have \<open>A \<turnstile> p \<^bold>\<longrightarrow> p \<^bold>\<or> q\<close> \<open>A \<turnstile> q \<^bold>\<longrightarrow> p \<^bold>\<or> q\<close>
       by (auto simp: A1)
     ultimately show \<open>(p \<^bold>\<or> q) \<in> V\<close>
       using Dis.prems deriv_in_maximal consequent_in_maximal by blast
   qed
 next
   case (Con p q)
   then show ?case
   proof safe
     assume \<open>(p \<^bold>\<and> q) \<in> V\<close>
     then have \<open>consistent A ({p} \<union> V)\<close> \<open>consistent A ({q} \<union> V)\<close>
       using \<open>consistent A V\<close> consistent_consequent' by fastforce+
     then have \<open>p \<in> V\<close> \<open>q \<in> V\<close>
       using \<open>maximal A V\<close> unfolding maximal_def by fast+
     then show \<open>canonical A, V \<Turnstile> (p \<^bold>\<and> q)\<close>
       using Con by simp
   next
     assume \<open>canonical A, V \<Turnstile> (p \<^bold>\<and> q)\<close>
     then have \<open>canonical A, V \<Turnstile> p\<close> \<open>canonical A, V \<Turnstile> q\<close>
       by auto
     then have \<open>p \<in> V\<close> \<open>q \<in> V\<close>
       using Con by auto
     moreover have \<open>A \<turnstile> p \<^bold>\<longrightarrow> q \<^bold>\<longrightarrow> p \<^bold>\<and> q\<close>
       by (auto simp: A1)
     ultimately show \<open>(p \<^bold>\<and> q) \<in> V\<close>
       using Con.prems deriv_in_maximal consequent_in_maximal by blast
   qed
 next
   case (Imp p q)
   then show ?case
   proof safe
     assume \<open>(p \<^bold>\<longrightarrow> q) \<in> V\<close>
     then have \<open>consistent A ({\<^bold>\<not> p \<^bold>\<or> q} \<union> V)\<close>
       using \<open>consistent A V\<close> consistent_consequent' by fastforce
     then have \<open>consistent A ({\<^bold>\<not> p} \<union> V) \<or> consistent A ({q} \<union> V)\<close>
       using \<open>consistent A V\<close> \<open>maximal A V\<close> consistent_disjuncts unfolding maximal_def by blast
     then have \<open>(\<^bold>\<not> p) \<in> V \<or> q \<in> V\<close>
       using \<open>maximal A V\<close> unfolding maximal_def by fast
     then have \<open>p \<notin> V \<or> q \<in> V\<close>
       using Imp.prems exactly_one_in_maximal by blast
     then show \<open>canonical A, V \<Turnstile> (p \<^bold>\<longrightarrow> q)\<close>
       using Imp by simp
   next
     assume \<open>canonical A, V \<Turnstile> (p \<^bold>\<longrightarrow> q)\<close>
     then consider \<open>\<not> canonical A, V \<Turnstile> p\<close> | \<open>canonical A, V \<Turnstile> q\<close>
       by auto
     then have \<open>p \<notin> V \<or> q \<in> V\<close>
       using Imp by auto
     then have \<open>(\<^bold>\<not> p) \<in> V \<or> q \<in> V\<close>
       using Imp.prems exactly_one_in_maximal by blast
     moreover have \<open>A \<turnstile> \<^bold>\<not> p \<^bold>\<longrightarrow> p \<^bold>\<longrightarrow> q\<close> \<open>A \<turnstile> q \<^bold>\<longrightarrow> p \<^bold>\<longrightarrow> q\<close>
       by (auto simp: A1)
     ultimately show \<open>(p \<^bold>\<longrightarrow> q) \<in> V\<close>
       using Imp.prems deriv_in_maximal consequent_in_maximal by blast
   qed
 next
   case (K i p)
   then show ?case
   proof safe
     assume \<open>K i p \<in> V\<close>
     then show \<open>canonical A, V \<Turnstile> K i p\<close>
       using K.hyps by auto
   next
     assume \<open>canonical A, V \<Turnstile> K i p\<close>
 
     have \<open>\<not> consistent A ({\<^bold>\<not> p} \<union> known V i)\<close>
     proof
       assume \<open>consistent A ({\<^bold>\<not> p} \<union> known V i)\<close>
       then obtain W where W: \<open>{\<^bold>\<not> p} \<union> known V i \<subseteq> W\<close> \<open>consistent A W\<close> \<open>maximal A W\<close>
         using \<open>consistent A V\<close> maximal_extension by blast
       then have \<open>canonical A, W \<Turnstile> \<^bold>\<not> p\<close>
         using K \<open>consistent A V\<close> exactly_one_in_maximal by auto
       moreover have \<open>W \<in> reach A i V\<close> \<open>W \<in> mcss A\<close>
         using W by simp_all
       ultimately have \<open>canonical A, V \<Turnstile> \<^bold>\<not> K i p\<close>
         by auto
       then show False
         using \<open>canonical A, V \<Turnstile> K i p\<close> by auto
     qed
 
     then obtain W where W:
       \<open>{\<^bold>\<not> p} \<union> W \<subseteq> {\<^bold>\<not> p} \<union> known V i\<close> \<open>(\<^bold>\<not> p) \<notin> W\<close> \<open>finite W\<close> \<open>\<not> consistent A ({\<^bold>\<not> p} \<union> W)\<close>
       using exists_finite_inconsistent by metis
 
     obtain L where L: \<open>set L = W\<close>
       using \<open>finite W\<close> finite_list by blast
 
     then have \<open>A \<turnstile> L \<^bold>\<leadsto> p\<close>
       using W(4) inconsistent_imply by blast
     then have \<open>A \<turnstile> K i (L \<^bold>\<leadsto> p)\<close>
       using R2 by fast
     then have \<open>A \<turnstile> map (K i) L \<^bold>\<leadsto> K i p\<close>
       using K_distrib_K_imp by fast
     then have \<open>(map (K i) L \<^bold>\<leadsto> K i p) \<in> V\<close>
       using deriv_in_maximal K.prems(1, 2) by blast
     then show \<open>K i p \<in> V\<close>
       using L W(1-2)
     proof (induct L arbitrary: W)
       case (Cons a L)
       then have \<open>K i a \<in> V\<close>
         by auto
       then have \<open>(map (K i) L \<^bold>\<leadsto> K i p) \<in> V\<close>
         using Cons(2) \<open>consistent A V\<close> \<open>maximal A V\<close> consequent_in_maximal by auto
       then show ?case
         using Cons by auto
     qed simp
   qed
 qed
 
 lemma canonical_model:
   assumes \<open>consistent A S\<close> and \<open>p \<in> S\<close>
   defines \<open>V \<equiv> Extend A S from_nat\<close> and \<open>M \<equiv> canonical A\<close>
   shows \<open>M, V \<Turnstile> p\<close> and \<open>consistent A V\<close> and \<open>maximal A V\<close>
 proof -
   have \<open>consistent A V\<close>
     using \<open>consistent A S\<close> unfolding V_def using consistent_Extend by blast
   have \<open>maximal A V\<close>
     unfolding V_def using maximal_Extend surj_from_nat by blast
 
   { fix x
     assume \<open>x \<in> S\<close>
     then have \<open>x \<in> V\<close>
       unfolding V_def using Extend_subset by blast
     then have \<open>M, V \<Turnstile> x\<close>
       unfolding M_def using truth_lemma \<open>consistent A V\<close> \<open>maximal A V\<close> by blast }
   then show \<open>M, V \<Turnstile> p\<close>
     using \<open>p \<in> S\<close> by blast+
   show \<open>consistent A V\<close> \<open>maximal A V\<close>
     by fact+
 qed
 
 subsection \<open>Completeness\<close>
 
-lemma imply_completeness:
-  fixes P :: \<open>(('i :: countable, 'i fm set) kripke) \<Rightarrow> bool\<close>
-  assumes \<open>\<forall>M. \<forall>w \<in> \<W> M. P M \<longrightarrow> (\<forall>q \<in> G. M, w \<Turnstile> q) \<longrightarrow> M, w \<Turnstile> p\<close>
-    and \<open>P (canonical A)\<close>
+abbreviation valid :: \<open>(('i :: countable, 'i fm set) kripke \<Rightarrow> bool) \<Rightarrow> 'i fm set \<Rightarrow> 'i fm \<Rightarrow> bool\<close>
+  where \<open>valid P G p \<equiv> \<forall>M. \<forall>w \<in> \<W> M. P M \<longrightarrow> (\<forall>q \<in> G. M, w \<Turnstile> q) \<longrightarrow> M, w \<Turnstile> p\<close>
+
+theorem strong_completeness:
+  assumes \<open>valid P G p\<close> and \<open>P (canonical A)\<close>
   shows \<open>\<exists>qs. set qs \<subseteq> G \<and> (A \<turnstile> qs \<^bold>\<leadsto> p)\<close>
 proof (rule ccontr)
   assume \<open>\<nexists>qs. set qs \<subseteq> G \<and> (A \<turnstile> qs \<^bold>\<leadsto> p)\<close>
   then have *: \<open>\<forall>qs. set qs \<subseteq> G \<longrightarrow> \<not> (A \<turnstile> (\<^bold>\<not> p) # qs \<^bold>\<leadsto> \<^bold>\<bottom>)\<close>
     using K_Boole by blast
 
   let ?S = \<open>{\<^bold>\<not> p} \<union> G\<close>
   let ?V = \<open>Extend A ?S from_nat\<close>
   let ?M = \<open>canonical A\<close>
 
   have \<open>consistent A ?S\<close>
     using * by (metis K_imply_Cons consistent_def inconsistent_subset)
   then have \<open>?M, ?V \<Turnstile> (\<^bold>\<not> p)\<close> \<open>\<forall>q \<in> G. ?M, ?V \<Turnstile> q\<close>
     using canonical_model by fastforce+
   moreover have \<open>?V \<in> mcss A\<close>
     using \<open>consistent A ?S\<close> consistent_Extend maximal_Extend surj_from_nat by blast
   ultimately have \<open>?M, ?V \<Turnstile> p\<close>
     using assms by simp
   then show False
     using \<open>?M, ?V \<Turnstile> (\<^bold>\<not> p)\<close> by simp
 qed
 
-abbreviation valid :: \<open>(('i :: countable, 'i fm set) kripke \<Rightarrow> bool) \<Rightarrow> 'i fm \<Rightarrow> bool\<close> where
-  \<open>valid P p \<equiv> \<forall>M. \<forall>w \<in> \<W> M. P M \<longrightarrow> M, w \<Turnstile> p\<close>
-
-theorem completeness:
-  assumes \<open>valid P p\<close> and \<open>P (canonical A)\<close>
+corollary completeness:
+  assumes \<open>valid P {} p\<close> and \<open>P (canonical A)\<close>
   shows \<open>A \<turnstile> p\<close>
-  using assms imply_completeness[where G=\<open>{}\<close>] by simp
+  using assms strong_completeness[where G=\<open>{}\<close>] by simp
 
-corollary completeness\<^sub>K:
-  assumes \<open>valid (\<lambda>_. True) p\<close>
+corollary completeness\<^sub>A:
+  assumes \<open>valid (\<lambda>_. True) {} p\<close>
   shows \<open>A \<turnstile> p\<close>
-  using assms completeness[where P=\<open>\<lambda>_. True\<close>] by blast
+  using assms completeness by blast
 
 section \<open>System K\<close>
 
 abbreviation SystemK :: \<open>'i fm \<Rightarrow> bool\<close> (\<open>\<turnstile>\<^sub>K _\<close> [20] 20) where
   \<open>\<turnstile>\<^sub>K p \<equiv> (\<lambda>_. False) \<turnstile> p\<close>
 
 lemma soundness\<^sub>K: \<open>\<turnstile>\<^sub>K p \<Longrightarrow> w \<in> \<W> M \<Longrightarrow> M, w \<Turnstile> p\<close>
   using soundness by metis
 
 abbreviation \<open>valid\<^sub>K \<equiv> valid (\<lambda>_. True)\<close>
 
-corollary
-  assumes \<open>valid\<^sub>K p\<close>
+theorem strong_completeness\<^sub>K:
+  assumes \<open>valid\<^sub>K G p\<close>
+  shows \<open>\<exists>qs. set qs \<subseteq> G \<and> (\<turnstile>\<^sub>K qs \<^bold>\<leadsto> p)\<close>
+  using assms strong_completeness[where P=\<open>\<lambda>_. True\<close>] by blast
+
+corollary completeness\<^sub>K:
+  assumes \<open>valid\<^sub>K {} p\<close>
   shows \<open>\<turnstile>\<^sub>K p\<close>
-  using completeness\<^sub>K assms .
+  using completeness\<^sub>A assms .
 
-theorem main\<^sub>K: \<open>valid\<^sub>K p \<longleftrightarrow> (\<turnstile>\<^sub>K p)\<close>
+theorem main\<^sub>K: \<open>valid\<^sub>K {} p \<longleftrightarrow> (\<turnstile>\<^sub>K p)\<close>
 proof
-  assume \<open>valid\<^sub>K p\<close>
+  assume \<open>valid\<^sub>K {} p\<close>
   with completeness show \<open>\<turnstile>\<^sub>K p\<close>
     by blast
 next
   assume \<open>\<turnstile>\<^sub>K p\<close>
-  with soundness\<^sub>K show \<open>valid\<^sub>K p\<close>
+  with soundness\<^sub>K show \<open>valid\<^sub>K {} p\<close>
     by fast
 qed
 
 corollary
-  assumes \<open>valid\<^sub>K p\<close> and \<open>w \<in> \<W> M\<close>
+  assumes \<open>valid\<^sub>K {} p\<close> and \<open>w \<in> \<W> M\<close>
   shows \<open>M, w \<Turnstile> p\<close>
 proof -
   have \<open>\<turnstile>\<^sub>K p\<close>
     using assms(1) unfolding main\<^sub>K .
   with soundness\<^sub>K assms(2) show \<open>M, w \<Turnstile> p\<close> by fast
 qed
 
 section \<open>System T\<close>
 
 text \<open>Also known as System M\<close>
 
 inductive AxT :: \<open>'i fm \<Rightarrow> bool\<close> where
   \<open>AxT (K i p \<^bold>\<longrightarrow> p)\<close>
 
 abbreviation SystemT :: \<open>'i fm \<Rightarrow> bool\<close> (\<open>\<turnstile>\<^sub>T _\<close> [20] 20) where
   \<open>\<turnstile>\<^sub>T p \<equiv> AxT \<turnstile> p\<close>
 
 lemma soundness_AxT: \<open>AxT p \<Longrightarrow> reflexive M \<Longrightarrow> w \<in> \<W> M \<Longrightarrow> M, w \<Turnstile> p\<close>
   by (induct p rule: AxT.induct) (meson truth)
 
 lemma soundness\<^sub>T: \<open>\<turnstile>\<^sub>T p \<Longrightarrow> reflexive M \<Longrightarrow> w \<in> \<W> M \<Longrightarrow> M, w \<Turnstile> p\<close>
   using soundness soundness_AxT .
 
 lemma AxT_reflexive:
   assumes \<open>AxT \<le> A\<close> and \<open>consistent A V\<close> and \<open>maximal A V\<close>
   shows \<open>V \<in> reach A i V\<close>
 proof -
   have \<open>(K i p \<^bold>\<longrightarrow> p) \<in> V\<close> for p
     using assms ax_in_maximal AxT.intros by fast
   then have \<open>p \<in> V\<close> if \<open>K i p \<in> V\<close> for p
     using that assms consequent_in_maximal by blast
   then show ?thesis
     using assms by blast
 qed
 
-lemma mcs\<^sub>T_reflexive:
+lemma reflexive\<^sub>T:
   assumes \<open>AxT \<le> A\<close>
   shows \<open>reflexive (canonical A)\<close>
   unfolding reflexive_def
 proof safe
   fix i V
   assume \<open>V \<in> \<W> (canonical A)\<close>
   then have \<open>consistent A V\<close> \<open>maximal A V\<close>
     by simp_all
   with AxT_reflexive assms have \<open>V \<in> reach A i V\<close> .
   then show \<open>V \<in> \<K> (canonical A) i V\<close>
     by simp
 qed
 
 abbreviation \<open>valid\<^sub>T \<equiv> valid reflexive\<close>
 
-lemma completeness\<^sub>T:
-  assumes \<open>valid\<^sub>T p\<close>
+theorem strong_completeness\<^sub>T:
+  assumes \<open>valid\<^sub>T G p\<close>
+  shows \<open>\<exists>qs. set qs \<subseteq> G \<and> (\<turnstile>\<^sub>T qs \<^bold>\<leadsto> p)\<close>
+  using assms strong_completeness reflexive\<^sub>T by blast
+
+corollary completeness\<^sub>T:
+  assumes \<open>valid\<^sub>T {} p\<close>
   shows \<open>\<turnstile>\<^sub>T p\<close>
-  using assms completeness mcs\<^sub>T_reflexive by blast
+  using assms completeness reflexive\<^sub>T by blast
 
-theorem main\<^sub>T: \<open>valid\<^sub>T p \<longleftrightarrow> (\<turnstile>\<^sub>T p)\<close>
+theorem main\<^sub>T: \<open>valid\<^sub>T {} p \<longleftrightarrow> (\<turnstile>\<^sub>T p)\<close>
   using soundness\<^sub>T completeness\<^sub>T by fast
 
 corollary
   assumes \<open>reflexive M\<close> \<open>w \<in> \<W> M\<close>
-  shows \<open>valid\<^sub>T p \<longrightarrow> M, w \<Turnstile> p\<close>
+  shows \<open>valid\<^sub>T {} p \<longrightarrow> M, w \<Turnstile> p\<close>
   using assms soundness\<^sub>T completeness\<^sub>T by fast
 
 section \<open>System KB\<close>
 
 inductive AxB :: \<open>'i fm \<Rightarrow> bool\<close> where
   \<open>AxB (p \<^bold>\<longrightarrow> K i (L i p))\<close>
 
 abbreviation SystemKB :: \<open>'i fm \<Rightarrow> bool\<close> (\<open>\<turnstile>\<^sub>K\<^sub>B _\<close> [20] 20) where
   \<open>\<turnstile>\<^sub>K\<^sub>B p \<equiv> AxB \<turnstile> p\<close>
 
 lemma soundness_AxB: \<open>AxB p \<Longrightarrow> symmetric M \<Longrightarrow> w \<in> \<W> M \<Longrightarrow> M, w \<Turnstile> p\<close>
   unfolding symmetric_def by (induct p rule: AxB.induct) auto
 
 lemma soundness\<^sub>K\<^sub>B: \<open>\<turnstile>\<^sub>K\<^sub>B p \<Longrightarrow> symmetric M \<Longrightarrow> w \<in> \<W> M \<Longrightarrow> M, w \<Turnstile> p\<close>
   using soundness soundness_AxB .
 
 lemma AxB_symmetric':
   assumes \<open>AxB \<le> A\<close> \<open>consistent A V\<close> \<open>maximal A V\<close> \<open>consistent A W\<close> \<open>maximal A W\<close>
     and \<open>W \<in> reach A i V\<close>
   shows \<open>V \<in> reach A i W\<close>
 proof -
   have \<open>\<forall>p. K i p \<in> W \<longrightarrow> p \<in> V\<close>
   proof (intro allI impI, rule ccontr)
     fix p
     assume \<open>K i p \<in> W\<close> \<open>p \<notin> V\<close>
     then have \<open>(\<^bold>\<not> p) \<in> V\<close>
       using assms(2-3) exactly_one_in_maximal by fast
     then have \<open>K i (L i (\<^bold>\<not> p)) \<in> V\<close>
       using assms(1-3) ax_in_maximal AxB.intros consequent_in_maximal by fast
     then have \<open>L i (\<^bold>\<not> p) \<in> W\<close>
       using \<open>W \<in> reach A i V\<close> by fast
     then have \<open>(\<^bold>\<not> K i p) \<in> W\<close>
       using assms(4-5) by (meson K_LK consistent_consequent maximal_def)
     then show False
       using \<open>K i p \<in> W\<close> assms(4-5) exactly_one_in_maximal by fast
   qed
   then have \<open>known W i \<subseteq> V\<close>
     by blast
   then show ?thesis
     using assms(2-3) by simp
 qed
 
-lemma mcs\<^sub>K\<^sub>B_symmetric:
+lemma symmetric\<^sub>K\<^sub>B:
   assumes \<open>AxB \<le> A\<close>
   shows \<open>symmetric (canonical A)\<close>
   unfolding symmetric_def
 proof (intro allI ballI)
   fix i V W
   assume \<open>V \<in> \<W> (canonical A)\<close> \<open>W \<in> \<W> (canonical A)\<close>
   then have \<open>consistent A V\<close> \<open>maximal A V\<close> \<open>consistent A W\<close> \<open>maximal A W\<close>
     by simp_all
   with AxB_symmetric' assms have \<open>W \<in> reach A i V \<longleftrightarrow> V \<in> reach A i W\<close>
     by metis
   then show
     \<open>(W \<in> \<K> (canonical A) i V) = (V \<in> \<K> (canonical A) i W)\<close>
     by simp
 qed
 
 abbreviation \<open>valid\<^sub>K\<^sub>B \<equiv> valid symmetric\<close>
 
-lemma completeness\<^sub>K\<^sub>B:
-  assumes \<open>valid\<^sub>K\<^sub>B p\<close>
+theorem strong_completeness\<^sub>K\<^sub>B:
+  assumes \<open>valid\<^sub>K\<^sub>B G p\<close>
+  shows \<open>\<exists>qs. set qs \<subseteq> G \<and> (\<turnstile>\<^sub>K\<^sub>B qs \<^bold>\<leadsto> p)\<close>
+  using assms strong_completeness symmetric\<^sub>K\<^sub>B by blast
+
+corollary completeness\<^sub>K\<^sub>B:
+  assumes \<open>valid\<^sub>K\<^sub>B {} p\<close>
   shows \<open>\<turnstile>\<^sub>K\<^sub>B p\<close>
-  using assms completeness mcs\<^sub>K\<^sub>B_symmetric by blast
+  using assms strong_completeness\<^sub>K\<^sub>B[where G=\<open>{}\<close>] by auto
 
-theorem main\<^sub>K\<^sub>B: \<open>valid\<^sub>K\<^sub>B p \<longleftrightarrow> (\<turnstile>\<^sub>K\<^sub>B p)\<close>
+theorem main\<^sub>K\<^sub>B: \<open>valid\<^sub>K\<^sub>B {} p \<longleftrightarrow> (\<turnstile>\<^sub>K\<^sub>B p)\<close>
   using soundness\<^sub>K\<^sub>B completeness\<^sub>K\<^sub>B by fast
 
 corollary
   assumes \<open>symmetric M\<close> \<open>w \<in> \<W> M\<close>
-  shows \<open>valid\<^sub>K\<^sub>B p \<longrightarrow> M, w \<Turnstile> p\<close>
+  shows \<open>valid\<^sub>K\<^sub>B {} p \<longrightarrow> M, w \<Turnstile> p\<close>
   using assms soundness\<^sub>K\<^sub>B completeness\<^sub>K\<^sub>B by fast
 
 section \<open>System K4\<close>
 
 inductive Ax4 :: \<open>'i fm \<Rightarrow> bool\<close> where
   \<open>Ax4 (K i p \<^bold>\<longrightarrow> K i (K i p))\<close>
 
 abbreviation SystemK4 :: \<open>'i fm \<Rightarrow> bool\<close> (\<open>\<turnstile>\<^sub>K\<^sub>4 _\<close> [20] 20) where
   \<open>\<turnstile>\<^sub>K\<^sub>4 p \<equiv> Ax4 \<turnstile> p\<close>
 
 lemma soundness_Ax4: \<open>Ax4 p \<Longrightarrow> transitive M \<Longrightarrow> w \<in> \<W> M \<Longrightarrow> M, w \<Turnstile> p\<close>
   by (induct p rule: Ax4.induct) (meson pos_introspection)
 
 lemma soundness\<^sub>K\<^sub>4: \<open>\<turnstile>\<^sub>K\<^sub>4 p \<Longrightarrow> transitive M \<Longrightarrow> w \<in> \<W> M \<Longrightarrow> M, w \<Turnstile> p\<close>
   using soundness soundness_Ax4 .
 
 lemma Ax4_transitive:
   assumes \<open>Ax4 \<le> A\<close> \<open>consistent A V\<close> \<open>maximal A V\<close>
     and \<open>W \<in> reach A i V\<close> \<open>U \<in> reach A i W\<close>
   shows \<open>U \<in> reach A i V\<close>
 proof -
   have \<open>(K i p \<^bold>\<longrightarrow> K i (K i p)) \<in> V\<close> for p
     using assms(1-3) ax_in_maximal Ax4.intros by fast
   then have \<open>K i (K i p) \<in> V\<close> if \<open>K i p \<in> V\<close> for p
     using that assms(2-3) consequent_in_maximal by blast
   then show ?thesis
     using assms(4-5) by blast
 qed
 
-lemma mcs\<^sub>K\<^sub>4_transitive:
+lemma transitive\<^sub>K\<^sub>4:
   assumes \<open>Ax4 \<le> A\<close>
   shows \<open>transitive (canonical A)\<close>
   unfolding transitive_def
 proof safe
   fix i U V W
   assume \<open>V \<in> \<W> (canonical A)\<close>
   then have \<open>consistent A V\<close> \<open>maximal A V\<close>
     by simp_all
   moreover assume
     \<open>W \<in> \<K> (canonical A) i V\<close>
     \<open>U \<in> \<K> (canonical A) i W\<close>
   ultimately have \<open>U \<in> reach A i V\<close>
     using Ax4_transitive assms by simp
   then show \<open>U \<in> \<K> (canonical A) i V\<close>
     by simp
 qed
 
 abbreviation \<open>valid\<^sub>K\<^sub>4 \<equiv> valid transitive\<close>
 
-lemma completeness\<^sub>K\<^sub>4:
-  assumes \<open>valid\<^sub>K\<^sub>4 p\<close>
+theorem strong_completeness\<^sub>K\<^sub>4:
+  assumes \<open>valid\<^sub>K\<^sub>4 G p\<close>
+  shows \<open>\<exists>qs. set qs \<subseteq> G \<and> (\<turnstile>\<^sub>K\<^sub>4 qs \<^bold>\<leadsto> p)\<close>
+  using assms strong_completeness transitive\<^sub>K\<^sub>4 by blast
+
+corollary completeness\<^sub>K\<^sub>4:
+  assumes \<open>valid\<^sub>K\<^sub>4 {} p\<close>
   shows \<open>\<turnstile>\<^sub>K\<^sub>4 p\<close>
-  using assms completeness mcs\<^sub>K\<^sub>4_transitive by blast
+  using assms strong_completeness\<^sub>K\<^sub>4[where G=\<open>{}\<close>] by auto
 
-theorem main\<^sub>K\<^sub>4: \<open>valid\<^sub>K\<^sub>4 p \<longleftrightarrow> (\<turnstile>\<^sub>K\<^sub>4 p)\<close>
+theorem main\<^sub>K\<^sub>4: \<open>valid\<^sub>K\<^sub>4 {} p \<longleftrightarrow> (\<turnstile>\<^sub>K\<^sub>4 p)\<close>
   using soundness\<^sub>K\<^sub>4 completeness\<^sub>K\<^sub>4 by fast
 
 corollary
   assumes \<open>transitive M\<close> \<open>w \<in> \<W> M\<close>
-  shows \<open>valid\<^sub>K\<^sub>4 p \<longrightarrow> M, w \<Turnstile> p\<close>
+  shows \<open>valid\<^sub>K\<^sub>4 {} p \<longrightarrow> M, w \<Turnstile> p\<close>
   using assms soundness\<^sub>K\<^sub>4 completeness\<^sub>K\<^sub>4 by fast
 
 section \<open>System S4\<close>
 
 abbreviation Or :: \<open>('a \<Rightarrow> bool) \<Rightarrow> ('a \<Rightarrow> bool) \<Rightarrow> 'a \<Rightarrow> bool\<close> (infixl \<open>\<oplus>\<close> 65) where
   \<open>A \<oplus> A' \<equiv> \<lambda>x. A x \<or> A' x\<close>
 
 abbreviation SystemS4 :: \<open>'i fm \<Rightarrow> bool\<close> (\<open>\<turnstile>\<^sub>S\<^sub>4 _\<close> [20] 20) where
   \<open>\<turnstile>\<^sub>S\<^sub>4 p \<equiv> AxT \<oplus> Ax4 \<turnstile> p\<close>
 
 lemma soundness_AxT4: \<open>(AxT \<oplus> Ax4) p \<Longrightarrow> reflexive M \<and> transitive M \<Longrightarrow> w \<in> \<W> M \<Longrightarrow> M, w \<Turnstile> p\<close>
   using soundness_AxT soundness_Ax4 by fast
 
 lemma soundness\<^sub>S\<^sub>4: \<open>\<turnstile>\<^sub>S\<^sub>4 p \<Longrightarrow> reflexive M \<and> transitive M \<Longrightarrow> w \<in> \<W> M \<Longrightarrow> M, w \<Turnstile> p\<close>
   using soundness soundness_AxT4 .
 
 abbreviation \<open>valid\<^sub>S\<^sub>4 \<equiv> valid refltrans\<close>
 
-lemma completeness\<^sub>S\<^sub>4:
-  assumes \<open>valid\<^sub>S\<^sub>4 p\<close>
+theorem strong_completeness\<^sub>S\<^sub>4:
+  assumes \<open>valid\<^sub>S\<^sub>4 G p\<close>
+  shows \<open>\<exists>qs. set qs \<subseteq> G \<and> (\<turnstile>\<^sub>S\<^sub>4 qs \<^bold>\<leadsto> p)\<close>
+  using assms strong_completeness[where P=refltrans]
+    reflexive\<^sub>T[where A=\<open>AxT \<oplus> Ax4\<close>] transitive\<^sub>K\<^sub>4[where A=\<open>AxT \<oplus> Ax4\<close>] by blast
+
+corollary completeness\<^sub>S\<^sub>4:
+  assumes \<open>valid\<^sub>S\<^sub>4 {} p\<close>
   shows \<open>\<turnstile>\<^sub>S\<^sub>4 p\<close>
-  using assms completeness[where P=refltrans] mcs\<^sub>T_reflexive[where A=\<open>AxT \<oplus> Ax4\<close>]
-    mcs\<^sub>K\<^sub>4_transitive[where A=\<open>AxT \<oplus> Ax4\<close>]
-  by blast
+  using assms strong_completeness\<^sub>S\<^sub>4[where G=\<open>{}\<close>] by auto
 
-theorem main\<^sub>S\<^sub>4: \<open>valid\<^sub>S\<^sub>4 p \<longleftrightarrow> (\<turnstile>\<^sub>S\<^sub>4 p)\<close>
+theorem main\<^sub>S\<^sub>4: \<open>valid\<^sub>S\<^sub>4 {} p \<longleftrightarrow> (\<turnstile>\<^sub>S\<^sub>4 p)\<close>
   using soundness\<^sub>S\<^sub>4 completeness\<^sub>S\<^sub>4 by fast
 
 corollary
   assumes \<open>reflexive M\<close> \<open>transitive M\<close> \<open>w \<in> \<W> M\<close>
-  shows \<open>valid\<^sub>S\<^sub>4 p \<longrightarrow> M, w \<Turnstile> p\<close>
+  shows \<open>valid\<^sub>S\<^sub>4 {} p \<longrightarrow> M, w \<Turnstile> p\<close>
   using assms soundness\<^sub>S\<^sub>4 completeness\<^sub>S\<^sub>4 by fast
 
 section \<open>System S5\<close>
 
 abbreviation SystemS5 :: \<open>'i fm \<Rightarrow> bool\<close> (\<open>\<turnstile>\<^sub>S\<^sub>5 _\<close> [20] 20) where
   \<open>\<turnstile>\<^sub>S\<^sub>5 p \<equiv> AxT \<oplus> AxB \<oplus> Ax4 \<turnstile> p\<close>
 
 abbreviation AxTB4 :: \<open>'i fm \<Rightarrow> bool\<close> where
   \<open>AxTB4 \<equiv> AxT \<oplus> AxB \<oplus> Ax4\<close>
 
 lemma soundness_AxTB4: \<open>AxTB4 p \<Longrightarrow> equivalence M \<Longrightarrow> w \<in> \<W> M \<Longrightarrow> M, w \<Turnstile> p\<close>
   using soundness_AxT soundness_AxB soundness_Ax4 by fast
 
 lemma soundness\<^sub>S\<^sub>5: \<open>\<turnstile>\<^sub>S\<^sub>5 p \<Longrightarrow> equivalence M \<Longrightarrow> w \<in> \<W> M \<Longrightarrow> M, w \<Turnstile> p\<close>
   using soundness soundness_AxTB4 .
 
 abbreviation \<open>valid\<^sub>S\<^sub>5 \<equiv> valid equivalence\<close>
 
-lemma completeness\<^sub>S\<^sub>5:
-  assumes \<open>valid\<^sub>S\<^sub>5 p\<close>
-  shows \<open>\<turnstile>\<^sub>S\<^sub>5 p\<close>
-  using assms completeness[where P=equivalence]
-    mcs\<^sub>T_reflexive[where A=AxTB4] mcs\<^sub>K\<^sub>B_symmetric[where A=AxTB4] mcs\<^sub>K\<^sub>4_transitive[where A=AxTB4]
+theorem strong_completeness\<^sub>S\<^sub>5:
+  assumes \<open>valid\<^sub>S\<^sub>5 G p\<close>
+  shows \<open>\<exists>qs. set qs \<subseteq> G \<and> (\<turnstile>\<^sub>S\<^sub>5 qs \<^bold>\<leadsto> p)\<close>
+  using assms strong_completeness[where P=equivalence]
+    reflexive\<^sub>T[where A=AxTB4] symmetric\<^sub>K\<^sub>B[where A=AxTB4] transitive\<^sub>K\<^sub>4[where A=AxTB4]
   by blast
 
-theorem main\<^sub>S\<^sub>5: \<open>valid\<^sub>S\<^sub>5 p \<longleftrightarrow> (\<turnstile>\<^sub>S\<^sub>5 p)\<close>
+corollary completeness\<^sub>S\<^sub>5:
+  assumes \<open>valid\<^sub>S\<^sub>5 {} p\<close>
+  shows \<open>\<turnstile>\<^sub>S\<^sub>5 p\<close>
+  using assms strong_completeness\<^sub>S\<^sub>5[where G=\<open>{}\<close>] by auto
+
+theorem main\<^sub>S\<^sub>5: \<open>valid\<^sub>S\<^sub>5 {} p \<longleftrightarrow> (\<turnstile>\<^sub>S\<^sub>5 p)\<close>
   using soundness\<^sub>S\<^sub>5 completeness\<^sub>S\<^sub>5 by fast
 
 corollary
   assumes \<open>equivalence M\<close> \<open>w \<in> \<W> M\<close>
-  shows \<open>valid\<^sub>S\<^sub>5 p \<longrightarrow> M, w \<Turnstile> p\<close>
+  shows \<open>valid\<^sub>S\<^sub>5 {} p \<longrightarrow> M, w \<Turnstile> p\<close>
   using assms soundness\<^sub>S\<^sub>5 completeness\<^sub>S\<^sub>5 by fast
 
 subsection \<open>Traditional formulation\<close>
 
 inductive SystemS5' :: \<open>'i fm \<Rightarrow> bool\<close> (\<open>\<turnstile>\<^sub>S\<^sub>5'' _\<close> [20] 20) where
   A1': \<open>tautology p \<Longrightarrow> \<turnstile>\<^sub>S\<^sub>5' p\<close>
 | A2': \<open>\<turnstile>\<^sub>S\<^sub>5' K i (p \<^bold>\<longrightarrow> q) \<^bold>\<longrightarrow> K i p \<^bold>\<longrightarrow> K i q\<close>
 | AT': \<open>\<turnstile>\<^sub>S\<^sub>5' K i p \<^bold>\<longrightarrow> p\<close>
 | A5': \<open>\<turnstile>\<^sub>S\<^sub>5' \<^bold>\<not> K i p \<^bold>\<longrightarrow> K i (\<^bold>\<not> K i p)\<close>
 | R1': \<open>\<turnstile>\<^sub>S\<^sub>5' p \<Longrightarrow> \<turnstile>\<^sub>S\<^sub>5' p \<^bold>\<longrightarrow> q \<Longrightarrow> \<turnstile>\<^sub>S\<^sub>5' q\<close>
 | R2': \<open>\<turnstile>\<^sub>S\<^sub>5' p \<Longrightarrow> \<turnstile>\<^sub>S\<^sub>5' K i p\<close>
 
 lemma S5'_trans: \<open>\<turnstile>\<^sub>S\<^sub>5' (p \<^bold>\<longrightarrow> q) \<^bold>\<longrightarrow> (q \<^bold>\<longrightarrow> r) \<^bold>\<longrightarrow> p \<^bold>\<longrightarrow> r\<close>
   by (simp add: A1')
 
 lemma S5'_L: \<open>\<turnstile>\<^sub>S\<^sub>5' p \<^bold>\<longrightarrow> L i p\<close>
 proof -
   have \<open>\<turnstile>\<^sub>S\<^sub>5' K i (\<^bold>\<not> p) \<^bold>\<longrightarrow> \<^bold>\<not> p\<close>
     using AT' by fast
   moreover have \<open>\<turnstile>\<^sub>S\<^sub>5' (P \<^bold>\<longrightarrow> \<^bold>\<not> Q) \<^bold>\<longrightarrow> Q \<^bold>\<longrightarrow> \<^bold>\<not> P\<close> for P Q :: \<open>'i fm\<close>
     using A1' by force
   ultimately show ?thesis
     using R1' by blast
 qed
 
 lemma S5'_B: \<open>\<turnstile>\<^sub>S\<^sub>5' p \<^bold>\<longrightarrow> K i (L i p)\<close>
   using A5' S5'_L R1' S5'_trans by metis
 
 lemma S5'_map_K:
   assumes \<open>\<turnstile>\<^sub>S\<^sub>5' p \<^bold>\<longrightarrow> q\<close>
   shows \<open>\<turnstile>\<^sub>S\<^sub>5' K i p \<^bold>\<longrightarrow> K i q\<close>
 proof -
   note \<open>\<turnstile>\<^sub>S\<^sub>5' p \<^bold>\<longrightarrow> q\<close>
   then have \<open>\<turnstile>\<^sub>S\<^sub>5' K i (p \<^bold>\<longrightarrow> q)\<close>
     using R2' by fast
   moreover have \<open>\<turnstile>\<^sub>S\<^sub>5' K i (p \<^bold>\<longrightarrow> q) \<^bold>\<longrightarrow> K i p \<^bold>\<longrightarrow> K i q\<close>
     using A2' by fast
   ultimately show ?thesis
     using R1' by fast
 qed
 
 lemma S5'_L_dual: \<open>\<turnstile>\<^sub>S\<^sub>5' \<^bold>\<not> L i (\<^bold>\<not> p) \<^bold>\<longrightarrow> K i p\<close>
 proof -
   have \<open>\<turnstile>\<^sub>S\<^sub>5' K i p \<^bold>\<longrightarrow> K i p\<close> \<open>\<turnstile>\<^sub>S\<^sub>5' \<^bold>\<not> \<^bold>\<not> p \<^bold>\<longrightarrow> p\<close>
     by (simp_all add: A1')
   then have \<open>\<turnstile>\<^sub>S\<^sub>5' K i (\<^bold>\<not> \<^bold>\<not> p) \<^bold>\<longrightarrow> K i p\<close>
     by (simp add: S5'_map_K)
   moreover have \<open>\<turnstile>\<^sub>S\<^sub>5' (P \<^bold>\<longrightarrow> Q) \<^bold>\<longrightarrow> (\<^bold>\<not> \<^bold>\<not> P \<^bold>\<longrightarrow> Q)\<close> for P Q :: \<open>'i fm\<close>
     by (simp add: A1')
   ultimately show \<open>\<turnstile>\<^sub>S\<^sub>5' \<^bold>\<not> \<^bold>\<not> K i (\<^bold>\<not> \<^bold>\<not> p) \<^bold>\<longrightarrow> K i p\<close>
     using R1' by blast
 qed
 
 lemma S5'_4: \<open>\<turnstile>\<^sub>S\<^sub>5' K i p \<^bold>\<longrightarrow> K i (K i p)\<close>
 proof -
   have \<open>\<turnstile>\<^sub>S\<^sub>5' L i (\<^bold>\<not> p) \<^bold>\<longrightarrow> K i (L i (\<^bold>\<not> p))\<close>
     using A5' by fast
   moreover have \<open>\<turnstile>\<^sub>S\<^sub>5' (P \<^bold>\<longrightarrow> Q) \<^bold>\<longrightarrow> \<^bold>\<not> Q \<^bold>\<longrightarrow> \<^bold>\<not> P\<close> for P Q :: \<open>'i fm\<close>
     using A1' by force
   ultimately have \<open>\<turnstile>\<^sub>S\<^sub>5' \<^bold>\<not> K i (L i (\<^bold>\<not> p)) \<^bold>\<longrightarrow> \<^bold>\<not> L i (\<^bold>\<not> p)\<close>
     using R1' by fast
   then have \<open>\<turnstile>\<^sub>S\<^sub>5' L i (K i (\<^bold>\<not> \<^bold>\<not> p)) \<^bold>\<longrightarrow> \<^bold>\<not> L i (\<^bold>\<not> p)\<close>
     by blast
   moreover have \<open>\<turnstile>\<^sub>S\<^sub>5' p \<^bold>\<longrightarrow> \<^bold>\<not> \<^bold>\<not> p\<close>
     by (simp add: A1')
   ultimately have \<open>\<turnstile>\<^sub>S\<^sub>5' L i (K i p) \<^bold>\<longrightarrow> \<^bold>\<not> L i (\<^bold>\<not> p)\<close>
     by (metis (no_types, opaque_lifting) R1' S5'_map_K S5'_trans)
   then have \<open>\<turnstile>\<^sub>S\<^sub>5' L i (K i p) \<^bold>\<longrightarrow> K i p\<close>
     by (meson S5'_L_dual R1' S5'_trans)
   then show ?thesis
     by (metis A2' R1' R2' S5'_B S5'_trans)
 qed
 
 lemma S5_S5': \<open>\<turnstile>\<^sub>S\<^sub>5 p \<Longrightarrow> \<turnstile>\<^sub>S\<^sub>5' p\<close>
 proof (induct p rule: AK.induct)
   case (A2 i p q)
   have \<open>\<turnstile>\<^sub>S\<^sub>5' K i (p \<^bold>\<longrightarrow> q) \<^bold>\<longrightarrow> K i p \<^bold>\<longrightarrow> K i q\<close>
     using A2' .
   moreover have \<open>\<turnstile>\<^sub>S\<^sub>5' (P \<^bold>\<longrightarrow> Q \<^bold>\<longrightarrow> R) \<^bold>\<longrightarrow> (Q \<^bold>\<and> P \<^bold>\<longrightarrow> R)\<close> for P Q R :: \<open>'i fm\<close>
     by (simp add: A1')
   ultimately show ?case
     using R1' by blast
 next
   case (Ax p)
   then show ?case
     using AT' S5'_B S5'_4
     by (metis Ax4.cases AxB.cases AxT.cases)
 qed (meson SystemS5'.intros)+
 
 lemma S5'_S5:
   fixes p :: \<open>('i :: countable) fm\<close>
   shows \<open>\<turnstile>\<^sub>S\<^sub>5' p \<Longrightarrow> \<turnstile>\<^sub>S\<^sub>5 p\<close>
 proof (induct p rule: SystemS5'.induct)
   case (AT' i p)
   then show ?case
     by (simp add: Ax AxT.intros)
 next
   case (A5' i p)
   then show ?case
     using completeness\<^sub>S\<^sub>5 neg_introspection by fast
 qed (meson AK.intros K_A2')+
 
-theorem main\<^sub>S\<^sub>5': \<open>valid\<^sub>S\<^sub>5 p \<longleftrightarrow> (\<turnstile>\<^sub>S\<^sub>5' p)\<close>
+theorem strong_completeness\<^sub>S\<^sub>5':
+  assumes \<open>valid\<^sub>S\<^sub>5 G p\<close>
+  shows \<open>\<exists>qs. set qs \<subseteq> G \<and> (\<turnstile>\<^sub>S\<^sub>5' qs \<^bold>\<leadsto> p)\<close>
+  using assms strong_completeness\<^sub>S\<^sub>5 S5_S5' S5'_S5 by blast
+
+theorem main\<^sub>S\<^sub>5': \<open>valid\<^sub>S\<^sub>5 {} p \<longleftrightarrow> (\<turnstile>\<^sub>S\<^sub>5' p)\<close>
   using main\<^sub>S\<^sub>5 S5_S5' S5'_S5 by blast
 
 section \<open>Acknowledgements\<close>
 
 text \<open>
 The formalization is inspired by Berghofer's formalization of Henkin-style completeness.
 
   \<^item> Stefan Berghofer:
   First-Order Logic According to Fitting.
   \<^url>\<open>https://www.isa-afp.org/entries/FOL-Fitting.shtml\<close>
 \<close>
 
 end
diff --git a/thys/Public_Announcement_Logic/PAL.thy b/thys/Public_Announcement_Logic/PAL.thy
--- a/thys/Public_Announcement_Logic/PAL.thy
+++ b/thys/Public_Announcement_Logic/PAL.thy
@@ -1,724 +1,810 @@
 (*
   File:      PAL.thy
   Author:    Asta Halkjær From
 
   This work is a formalization of public announcement logic with countably many agents.
   It includes proofs of soundness and completeness for a variant of the axiom system
     PA + DIST! + NEC!.
   The completeness proof builds on the Epistemic Logic theory.
 *)
 
-theory PAL imports "Epistemic_Logic.Epistemic_Logic" begin
+theory PAL imports "Epistemic_Logic" begin
 
 section \<open>Syntax\<close>
 
 datatype 'i pfm
   = FF (\<open>\<^bold>\<bottom>\<^sub>!\<close>)
   | Pro' id (\<open>Pro\<^sub>!\<close>)
   | Dis \<open>'i pfm\<close> \<open>'i pfm\<close> (infixr \<open>\<^bold>\<or>\<^sub>!\<close> 30)
   | Con \<open>'i pfm\<close> \<open>'i pfm\<close> (infixr \<open>\<^bold>\<and>\<^sub>!\<close> 35)
   | Imp \<open>'i pfm\<close> \<open>'i pfm\<close> (infixr \<open>\<^bold>\<longrightarrow>\<^sub>!\<close> 25)
   | K' 'i \<open>'i pfm\<close> (\<open>K\<^sub>!\<close>)
   | Ann \<open>'i pfm\<close> \<open>'i pfm\<close> (\<open>[_]\<^sub>! _\<close> [50, 50] 50)
 
 abbreviation PIff :: \<open>'i pfm \<Rightarrow> 'i pfm \<Rightarrow> 'i pfm\<close> (infixr \<open>\<^bold>\<longleftrightarrow>\<^sub>!\<close> 25) where
   \<open>p \<^bold>\<longleftrightarrow>\<^sub>! q \<equiv> (p \<^bold>\<longrightarrow>\<^sub>! q) \<^bold>\<and>\<^sub>! (q \<^bold>\<longrightarrow>\<^sub>! p)\<close>
 
 abbreviation PNeg (\<open>\<^bold>\<not>\<^sub>! _\<close> [40] 40) where
   \<open>\<^bold>\<not>\<^sub>! p \<equiv> p \<^bold>\<longrightarrow>\<^sub>! \<^bold>\<bottom>\<^sub>!\<close>
 
 abbreviation PL (\<open>L\<^sub>!\<close>) where
   \<open>L\<^sub>! i p \<equiv> (\<^bold>\<not>\<^sub>! (K\<^sub>! i (\<^bold>\<not>\<^sub>! p)))\<close>
 
 section \<open>Semantics\<close>
 
 fun
   psemantics :: \<open>('i, 'w) kripke \<Rightarrow> 'w \<Rightarrow> 'i pfm \<Rightarrow> bool\<close> (\<open>_, _ \<Turnstile>\<^sub>! _\<close> [50, 50] 50) and
   restrict :: \<open>('i, 'w) kripke \<Rightarrow> 'i pfm \<Rightarrow> ('i, 'w) kripke\<close> where
   \<open>(M, w \<Turnstile>\<^sub>! \<^bold>\<bottom>\<^sub>!) = False\<close>
 | \<open>(M, w \<Turnstile>\<^sub>! Pro\<^sub>! x) = \<pi> M w x\<close>
 | \<open>(M, w \<Turnstile>\<^sub>! (p \<^bold>\<or>\<^sub>! q)) = ((M, w \<Turnstile>\<^sub>! p) \<or> (M, w \<Turnstile>\<^sub>! q))\<close>
 | \<open>(M, w \<Turnstile>\<^sub>! (p \<^bold>\<and>\<^sub>! q)) = ((M, w \<Turnstile>\<^sub>! p) \<and> (M, w \<Turnstile>\<^sub>! q))\<close>
 | \<open>(M, w \<Turnstile>\<^sub>! (p \<^bold>\<longrightarrow>\<^sub>! q)) = ((M, w \<Turnstile>\<^sub>! p) \<longrightarrow> (M, w \<Turnstile>\<^sub>! q))\<close>
 | \<open>(M, w \<Turnstile>\<^sub>! K\<^sub>! i p) = (\<forall>v \<in> \<W> M \<inter> \<K> M i w. M, v \<Turnstile>\<^sub>! p)\<close>
 | \<open>(M, w \<Turnstile>\<^sub>! [r]\<^sub>! p) = ((M, w \<Turnstile>\<^sub>! r) \<longrightarrow> (restrict M r, w \<Turnstile>\<^sub>! p))\<close>
 | \<open>restrict M p = Kripke {w. w \<in> \<W> M \<and> M, w \<Turnstile>\<^sub>! p} (\<pi> M) (\<K> M)\<close>
 
 primrec static :: \<open>'i pfm \<Rightarrow> bool\<close> where
   \<open>static \<^bold>\<bottom>\<^sub>! = True\<close>
 | \<open>static (Pro\<^sub>! _) = True\<close>
 | \<open>static (p \<^bold>\<or>\<^sub>! q) = (static p \<and> static q)\<close>
 | \<open>static (p \<^bold>\<and>\<^sub>! q) = (static p \<and> static q)\<close>
 | \<open>static (p \<^bold>\<longrightarrow>\<^sub>! q) = (static p \<and> static q)\<close>
 | \<open>static (K\<^sub>! i p) = static p\<close>
 | \<open>static ([r]\<^sub>! p) = False\<close>
 
 primrec lower :: \<open>'i pfm \<Rightarrow> 'i fm\<close> where
   \<open>lower \<^bold>\<bottom>\<^sub>! = \<^bold>\<bottom>\<close>
 | \<open>lower (Pro\<^sub>! x) = Pro x\<close>
 | \<open>lower (p \<^bold>\<or>\<^sub>! q) = (lower p \<^bold>\<or> lower q)\<close>
 | \<open>lower (p \<^bold>\<and>\<^sub>! q) = (lower p \<^bold>\<and> lower q)\<close>
 | \<open>lower (p \<^bold>\<longrightarrow>\<^sub>! q) = (lower p \<^bold>\<longrightarrow> lower q)\<close>
 | \<open>lower (K\<^sub>! i p) = K i (lower p)\<close>
 | \<open>lower ([r]\<^sub>! p) = undefined\<close>
 
 primrec lift :: \<open>'i fm \<Rightarrow> 'i pfm\<close> where
   \<open>lift \<^bold>\<bottom> = \<^bold>\<bottom>\<^sub>!\<close>
 | \<open>lift (Pro x) = Pro\<^sub>! x\<close>
 | \<open>lift (p \<^bold>\<or> q) = (lift p \<^bold>\<or>\<^sub>! lift q)\<close>
 | \<open>lift (p \<^bold>\<and> q) = (lift p \<^bold>\<and>\<^sub>! lift q)\<close>
 | \<open>lift (p \<^bold>\<longrightarrow> q) = (lift p \<^bold>\<longrightarrow>\<^sub>! lift q)\<close>
 | \<open>lift (K i p) = K\<^sub>! i (lift p)\<close>
 
 lemma lower_semantics:
   assumes \<open>static p\<close>
   shows \<open>(M, w \<Turnstile> lower p) \<longleftrightarrow> (M, w \<Turnstile>\<^sub>! p)\<close>
   using assms by (induct p arbitrary: w) simp_all
 
 lemma lift_semantics: \<open>(M, w \<Turnstile> p) \<longleftrightarrow> (M, w \<Turnstile>\<^sub>! lift p)\<close>
   by (induct p arbitrary: w) simp_all
 
 lemma lower_lift: \<open>lower (lift p) = p\<close>
   by (induct p) simp_all
 
 lemma lift_lower: \<open>static p \<Longrightarrow> lift (lower p) = p\<close>
   by (induct p) simp_all
 
 section \<open>Soundness of Reduction\<close>
 
 primrec reduce' :: \<open>'i pfm \<Rightarrow> 'i pfm \<Rightarrow> 'i pfm\<close> where
   \<open>reduce' r \<^bold>\<bottom>\<^sub>! = (r \<^bold>\<longrightarrow>\<^sub>! \<^bold>\<bottom>\<^sub>!)\<close>
 | \<open>reduce' r (Pro\<^sub>! x) = (r \<^bold>\<longrightarrow>\<^sub>! Pro\<^sub>! x)\<close>
 | \<open>reduce' r (p \<^bold>\<or>\<^sub>! q) = (reduce' r p \<^bold>\<or>\<^sub>! reduce' r q)\<close>
 | \<open>reduce' r (p \<^bold>\<and>\<^sub>! q) = (reduce' r p \<^bold>\<and>\<^sub>! reduce' r q)\<close>
 | \<open>reduce' r (p \<^bold>\<longrightarrow>\<^sub>! q) = (reduce' r p \<^bold>\<longrightarrow>\<^sub>! reduce' r q)\<close>
 | \<open>reduce' r (K\<^sub>! i p) = (r \<^bold>\<longrightarrow>\<^sub>! K\<^sub>! i (reduce' r p))\<close>
 | \<open>reduce' r ([p]\<^sub>! q) = undefined\<close>
 
 primrec reduce :: \<open>'i pfm \<Rightarrow> 'i pfm\<close> where
   \<open>reduce \<^bold>\<bottom>\<^sub>! = \<^bold>\<bottom>\<^sub>!\<close>
 | \<open>reduce (Pro\<^sub>! x) = Pro\<^sub>! x\<close>
 | \<open>reduce (p \<^bold>\<or>\<^sub>! q) = (reduce p \<^bold>\<or>\<^sub>! reduce q)\<close>
 | \<open>reduce (p \<^bold>\<and>\<^sub>! q) = (reduce p \<^bold>\<and>\<^sub>! reduce q)\<close>
 | \<open>reduce (p \<^bold>\<longrightarrow>\<^sub>! q) = (reduce p \<^bold>\<longrightarrow>\<^sub>! reduce q)\<close>
 | \<open>reduce (K\<^sub>! i p) = K\<^sub>! i (reduce p)\<close>
 | \<open>reduce ([r]\<^sub>! p) = reduce' (reduce r) (reduce p)\<close>
 
 lemma static_reduce': \<open>static p \<Longrightarrow> static r \<Longrightarrow> static (reduce' r p)\<close>
   by (induct p) simp_all
 
 lemma static_reduce: \<open>static (reduce p)\<close>
   by (induct p) (simp_all add: static_reduce')
 
 lemma reduce'_semantics:
   assumes \<open>static q\<close>
   shows \<open>((M, w \<Turnstile>\<^sub>! [p]\<^sub>! (q))) = (M, w \<Turnstile>\<^sub>! reduce' p q)\<close>
   using assms by (induct q arbitrary: w) auto
 
 lemma reduce_semantics: \<open>(M, w \<Turnstile>\<^sub>! p) = (M, w \<Turnstile>\<^sub>! reduce p)\<close>
 proof (induct p arbitrary: M w)
   case (Ann p q)
   then show ?case
     using reduce'_semantics static_reduce by fastforce
 qed simp_all
 
+section \<open>Chains of Implications\<close>
+
+primrec implyP :: \<open>'i pfm list \<Rightarrow> 'i pfm \<Rightarrow> 'i pfm\<close> (infixr \<open>\<^bold>\<leadsto>\<^sub>!\<close> 26) where
+  \<open>([] \<^bold>\<leadsto>\<^sub>! q) = q\<close>
+| \<open>(p # ps \<^bold>\<leadsto>\<^sub>! q) = (p \<^bold>\<longrightarrow>\<^sub>! ps \<^bold>\<leadsto>\<^sub>! q)\<close>
+
+lemma lift_imply: \<open>lift (ps \<^bold>\<leadsto> q) = (map lift ps \<^bold>\<leadsto>\<^sub>! lift q)\<close>
+  by (induct ps) auto
+
+lemma reduce_imply: \<open>reduce (ps \<^bold>\<leadsto>\<^sub>! q) = (map reduce ps \<^bold>\<leadsto>\<^sub>! reduce q)\<close>
+  by (induct ps) auto
+
 section \<open>Proof System\<close>
 
 primrec peval :: \<open>(id \<Rightarrow> bool) \<Rightarrow> ('i pfm \<Rightarrow> bool) \<Rightarrow> 'i pfm \<Rightarrow> bool\<close> where
   \<open>peval _ _ \<^bold>\<bottom>\<^sub>! = False\<close>
 | \<open>peval g _ (Pro\<^sub>! x) = g x\<close>
 | \<open>peval g h (p \<^bold>\<or>\<^sub>! q) = (peval g h p \<or> peval g h q)\<close>
 | \<open>peval g h (p \<^bold>\<and>\<^sub>! q) = (peval g h p \<and> peval g h q)\<close>
 | \<open>peval g h (p \<^bold>\<longrightarrow>\<^sub>! q) = (peval g h p \<longrightarrow> peval g h q)\<close>
 | \<open>peval _ h (K\<^sub>! i p) = h (K\<^sub>! i p)\<close>
 | \<open>peval _ h ([r]\<^sub>! p) = h ([r]\<^sub>! p)\<close>
 
 abbreviation \<open>ptautology p \<equiv> \<forall>g h. peval g h p\<close>
 
 inductive PAK :: \<open>('i pfm \<Rightarrow> bool) \<Rightarrow> 'i pfm \<Rightarrow> bool\<close> (\<open>_ \<turnstile>\<^sub>! _\<close> [20, 20] 20)
   for A :: \<open>'i pfm \<Rightarrow> bool\<close> where
     PA1: \<open>ptautology p \<Longrightarrow> A \<turnstile>\<^sub>! p\<close>
   | PA2: \<open>A \<turnstile>\<^sub>! K\<^sub>! i p \<^bold>\<and>\<^sub>! K\<^sub>! i (p \<^bold>\<longrightarrow>\<^sub>! q) \<^bold>\<longrightarrow>\<^sub>! K\<^sub>! i q\<close>
   | PAx: \<open>A p \<Longrightarrow> A \<turnstile>\<^sub>! p\<close>
   | PR1: \<open>A \<turnstile>\<^sub>! p \<Longrightarrow> A \<turnstile>\<^sub>! p \<^bold>\<longrightarrow>\<^sub>! q \<Longrightarrow> A \<turnstile>\<^sub>! q\<close>
   | PR2: \<open>A \<turnstile>\<^sub>! p \<Longrightarrow> A \<turnstile>\<^sub>! K\<^sub>! i p\<close>
   | PFF: \<open>A \<turnstile>\<^sub>! [r]\<^sub>! \<^bold>\<bottom>\<^sub>! \<^bold>\<longleftrightarrow>\<^sub>! (r \<^bold>\<longrightarrow>\<^sub>! \<^bold>\<bottom>\<^sub>!)\<close>
   | PPro: \<open>A \<turnstile>\<^sub>! [r]\<^sub>! Pro\<^sub>! x \<^bold>\<longleftrightarrow>\<^sub>! (r \<^bold>\<longrightarrow>\<^sub>! Pro\<^sub>! x)\<close>
   | PDis: \<open>A \<turnstile>\<^sub>! [r]\<^sub>! (p \<^bold>\<or>\<^sub>! q) \<^bold>\<longleftrightarrow>\<^sub>! [r]\<^sub>! p \<^bold>\<or>\<^sub>! [r]\<^sub>! q\<close>
   | PCon: \<open>A \<turnstile>\<^sub>! [r]\<^sub>! (p \<^bold>\<and>\<^sub>! q) \<^bold>\<longleftrightarrow>\<^sub>! [r]\<^sub>! p \<^bold>\<and>\<^sub>! [r]\<^sub>! q\<close>
   | PImp: \<open>A \<turnstile>\<^sub>! ([r]\<^sub>! (p \<^bold>\<longrightarrow>\<^sub>! q)) \<^bold>\<longleftrightarrow>\<^sub>! ([r]\<^sub>! p \<^bold>\<longrightarrow>\<^sub>! [r]\<^sub>! q)\<close>
   | PK: \<open>A \<turnstile>\<^sub>! ([r]\<^sub>! K\<^sub>! i p) \<^bold>\<longleftrightarrow>\<^sub>! (r \<^bold>\<longrightarrow>\<^sub>! K\<^sub>! i ([r]\<^sub>! p))\<close>
   | PAnn: \<open>A \<turnstile>\<^sub>! p \<Longrightarrow> A \<turnstile>\<^sub>! [r]\<^sub>! p\<close>
 
 lemma eval_peval: \<open>eval h (g o lift) p = peval h g (lift p)\<close>
   by (induct p) simp_all
 
 lemma tautology_ptautology: \<open>tautology p \<Longrightarrow> ptautology (lift p)\<close>
   using eval_peval by blast
 
 theorem AK_PAK: \<open>A o lift \<turnstile> p \<Longrightarrow> A \<turnstile>\<^sub>! lift p\<close>
   by (induct p rule: AK.induct) (auto intro: PAK.intros(1-5) simp: tautology_ptautology)
 
-abbreviation validP :: \<open>(('i :: countable, 'i fm set) kripke \<Rightarrow> bool) \<Rightarrow> 'i pfm \<Rightarrow> bool\<close> (\<open>valid\<^sub>!\<close>)
-  where \<open>valid\<^sub>! P p \<equiv> \<forall>M. \<forall>w \<in> \<W> M. P M \<longrightarrow> M, w \<Turnstile>\<^sub>! p\<close>
+abbreviation validP
+  :: \<open>(('i :: countable, 'i fm set) kripke \<Rightarrow> bool) \<Rightarrow> 'i pfm set \<Rightarrow> 'i pfm \<Rightarrow> bool\<close> (\<open>valid\<^sub>!\<close>)
+  where \<open>valid\<^sub>! P G p \<equiv> \<forall>M. \<forall>w \<in> \<W> M. P M \<longrightarrow> (\<forall>q \<in> G. M, w \<Turnstile>\<^sub>! q) \<longrightarrow> M, w \<Turnstile>\<^sub>! p\<close>
 
-theorem static_completeness:
-  assumes \<open>static p\<close> and \<open>valid\<^sub>! P p\<close>
-    and \<open>valid P (lower p) \<Longrightarrow> A o lift \<turnstile> lower p\<close>
-  shows \<open>A \<turnstile>\<^sub>! p\<close>
+lemma set_map_inv:
+  assumes \<open>set xs \<subseteq> f ` X\<close>
+  shows \<open>\<exists>ys. set ys \<subseteq> X \<and> map f ys = xs\<close>
+  using assms
+proof (induct xs)
+  case (Cons x xs)
+  then obtain ys where \<open>set ys \<subseteq> X\<close> \<open>map f ys = xs\<close>
+    by auto
+  moreover obtain y where \<open>y \<in> X\<close> \<open>f y = x\<close>
+    using Cons.prems by auto
+  ultimately have \<open>set (y # ys) \<subseteq> X\<close> \<open>map f (y # ys) = x # xs\<close>
+    by simp_all
+  then show ?case
+    by meson
+qed simp
+
+theorem strong_static_completeness:
+  assumes \<open>static p\<close> and \<open>\<forall>q \<in> G. static q\<close> and \<open>valid\<^sub>! P G p\<close>
+    and \<open>valid P (lower ` G) (lower p) \<Longrightarrow>
+      \<exists>qs. set qs \<subseteq> lower ` G \<and> (A o lift \<turnstile> qs \<^bold>\<leadsto> lower p)\<close>
+  shows \<open>\<exists>qs. set qs \<subseteq> G \<and> (A \<turnstile>\<^sub>! qs \<^bold>\<leadsto>\<^sub>! p)\<close>
 proof -
-  have \<open>valid P (lower p)\<close>
+  have \<open>valid P (lower ` G) (lower p)\<close>
     using assms by (simp add: lower_semantics)
-  then have \<open>A o lift \<turnstile> lower p\<close>
-    using assms(3) by fast
-  then have \<open>A \<turnstile>\<^sub>! lift (lower p)\<close>
+  then have \<open>\<exists>qs. set qs \<subseteq> lower ` G \<and> (A o lift \<turnstile> qs \<^bold>\<leadsto> lower p)\<close>
+    using assms(4) by fast
+  then obtain qs where \<open>set qs \<subseteq> G\<close> and \<open>A o lift \<turnstile> map lower qs \<^bold>\<leadsto> lower p\<close>
+    using set_map_inv by blast
+  then have \<open>A \<turnstile>\<^sub>! lift (map lower qs \<^bold>\<leadsto> lower p)\<close>
     using AK_PAK by fast
+  then have \<open>A \<turnstile>\<^sub>! map lift (map lower qs) \<^bold>\<leadsto>\<^sub>! lift (lower p)\<close>
+    using lift_imply by metis
+  then have \<open>A \<turnstile>\<^sub>! map (lift o lower) qs \<^bold>\<leadsto>\<^sub>! lift (lower p)\<close>
+    by simp
   then show ?thesis
-    using assms(1) lift_lower by metis
+    using assms(1-2) \<open>set qs \<subseteq> G\<close> lift_lower
+    by (metis (mono_tags, lifting) comp_apply map_idI subset_eq)
 qed
 
+corollary static_completeness:
+  assumes \<open>static p\<close> and \<open>valid\<^sub>! P {} p\<close>
+    and \<open>valid P {} (lower p) \<Longrightarrow> A o lift \<turnstile> lower p\<close>
+  shows \<open>A \<turnstile>\<^sub>! p\<close>
+  using assms strong_static_completeness[where G=\<open>{}\<close> and p=p] by simp
+
 corollary
-  assumes \<open>static p\<close> \<open>valid\<^sub>! (\<lambda>_. True) p\<close>
+  assumes \<open>static p\<close> \<open>valid\<^sub>! (\<lambda>_. True) {} p\<close>
   shows \<open>A \<turnstile>\<^sub>! p\<close>
-  using assms static_completeness[where P=\<open>\<lambda>_. True\<close>] completeness\<^sub>K by metis
+  using assms static_completeness[where P=\<open>\<lambda>_. True\<close> and p=p] completeness\<^sub>A by blast
 
 section \<open>Soundness\<close>
 
 lemma peval_semantics: \<open>peval (val w) (\<lambda>q. Kripke W val r, w \<Turnstile>\<^sub>! q) p = (Kripke W val r, w \<Turnstile>\<^sub>! p)\<close>
   by (induct p) simp_all
 
 lemma ptautology:
   assumes \<open>ptautology p\<close>
   shows \<open>M, w \<Turnstile>\<^sub>! p\<close>
 proof -
   from assms have \<open>peval (g w) (\<lambda>q. Kripke W g r, w \<Turnstile>\<^sub>! q) p\<close> for W g r
     by simp
   then have \<open>Kripke W g r, w \<Turnstile>\<^sub>! p\<close> for W g r
     using peval_semantics by fast
   then show \<open>M, w \<Turnstile>\<^sub>! p\<close>
     by (metis kripke.collapse)
 qed
 
 theorem soundness:
   assumes
     \<open>\<And>M p w. A p \<Longrightarrow> P M \<Longrightarrow> w \<in> \<W> M \<Longrightarrow> M, w \<Turnstile>\<^sub>! p\<close>
     \<open>\<And>M p. P M \<Longrightarrow> P (restrict M p)\<close>
   shows \<open>A \<turnstile>\<^sub>! p \<Longrightarrow> P M \<Longrightarrow> w \<in> \<W> M \<Longrightarrow> M, w \<Turnstile>\<^sub>! p\<close>
 proof (induct p arbitrary: M w rule: PAK.induct)
   case (PAnn p r)
   moreover have \<open>P (restrict M r)\<close>
     using PAnn(3) assms(2) by simp
   ultimately show ?case
     by simp
 qed (simp_all add: assms ptautology)
 
 corollary \<open>(\<lambda>_. False) \<turnstile>\<^sub>! p \<Longrightarrow> w \<in> \<W> M \<Longrightarrow> M, w \<Turnstile>\<^sub>! p\<close>
   using soundness[where P=\<open>\<lambda>_. True\<close>] by metis
 
 section \<open>Completeness\<close>
 
 lemma ConE:
   assumes \<open>A \<turnstile>\<^sub>! p \<^bold>\<and>\<^sub>! q\<close>
   shows \<open>A \<turnstile>\<^sub>! p\<close> \<open>A \<turnstile>\<^sub>! q\<close>
   using assms by (metis PA1 PR1 peval.simps(4-5))+
 
 lemma Iff_Dis:
   assumes \<open>A \<turnstile>\<^sub>! p \<^bold>\<longleftrightarrow>\<^sub>! p'\<close> \<open>A \<turnstile>\<^sub>! q \<^bold>\<longleftrightarrow>\<^sub>! q'\<close>
   shows \<open>A \<turnstile>\<^sub>! ((p \<^bold>\<or>\<^sub>! q) \<^bold>\<longleftrightarrow>\<^sub>! (p' \<^bold>\<or>\<^sub>! q'))\<close>
 proof -
   have \<open>A \<turnstile>\<^sub>! (p \<^bold>\<longleftrightarrow>\<^sub>! p') \<^bold>\<longrightarrow>\<^sub>! (q \<^bold>\<longleftrightarrow>\<^sub>! q') \<^bold>\<longrightarrow>\<^sub>! ((p \<^bold>\<or>\<^sub>! q) \<^bold>\<longleftrightarrow>\<^sub>! (p' \<^bold>\<or>\<^sub>! q'))\<close>
     by (simp add: PA1)
   then show ?thesis
     using assms PR1 by blast
 qed
 
 lemma Iff_Con:
   assumes \<open>A \<turnstile>\<^sub>! p \<^bold>\<longleftrightarrow>\<^sub>! p'\<close> \<open>A \<turnstile>\<^sub>! q \<^bold>\<longleftrightarrow>\<^sub>! q'\<close>
   shows \<open>A \<turnstile>\<^sub>! (p \<^bold>\<and>\<^sub>! q) \<^bold>\<longleftrightarrow>\<^sub>! (p' \<^bold>\<and>\<^sub>! q')\<close>
 proof -
   have \<open>A \<turnstile>\<^sub>! (p \<^bold>\<longleftrightarrow>\<^sub>! p') \<^bold>\<longrightarrow>\<^sub>! (q \<^bold>\<longleftrightarrow>\<^sub>! q') \<^bold>\<longrightarrow>\<^sub>! ((p \<^bold>\<and>\<^sub>! q) \<^bold>\<longleftrightarrow>\<^sub>! (p' \<^bold>\<and>\<^sub>! q'))\<close>
     by (simp add: PA1)
   then show ?thesis
     using assms PR1 by blast
 qed
 
 lemma Iff_Imp:
   assumes \<open>A \<turnstile>\<^sub>! p \<^bold>\<longleftrightarrow>\<^sub>! p'\<close> \<open>A \<turnstile>\<^sub>! q \<^bold>\<longleftrightarrow>\<^sub>! q'\<close>
   shows \<open>A \<turnstile>\<^sub>! ((p \<^bold>\<longrightarrow>\<^sub>! q) \<^bold>\<longleftrightarrow>\<^sub>! (p' \<^bold>\<longrightarrow>\<^sub>! q'))\<close>
 proof -
   have \<open>A \<turnstile>\<^sub>! (p \<^bold>\<longleftrightarrow>\<^sub>! p') \<^bold>\<longrightarrow>\<^sub>! (q \<^bold>\<longleftrightarrow>\<^sub>! q') \<^bold>\<longrightarrow>\<^sub>! ((p \<^bold>\<longrightarrow>\<^sub>! q) \<^bold>\<longleftrightarrow>\<^sub>! (p' \<^bold>\<longrightarrow>\<^sub>! q'))\<close>
     by (simp add: PA1)
   then show ?thesis
     using assms PR1 by blast
 qed
 
 lemma Iff_sym: \<open>(A \<turnstile>\<^sub>! p \<^bold>\<longleftrightarrow>\<^sub>! q) = (A \<turnstile>\<^sub>! q \<^bold>\<longleftrightarrow>\<^sub>! p)\<close>
 proof -
   have \<open>A \<turnstile>\<^sub>! (p \<^bold>\<longleftrightarrow>\<^sub>! q) \<^bold>\<longleftrightarrow>\<^sub>! (q \<^bold>\<longleftrightarrow>\<^sub>! p)\<close>
     by (simp add: PA1)
   then show ?thesis
     using PR1 ConE by blast
 qed
 
 lemma Iff_Iff:
   assumes \<open>A \<turnstile>\<^sub>! p \<^bold>\<longleftrightarrow>\<^sub>! p'\<close> \<open>A \<turnstile>\<^sub>! p \<^bold>\<longleftrightarrow>\<^sub>! q\<close>
   shows \<open>A \<turnstile>\<^sub>! p' \<^bold>\<longleftrightarrow>\<^sub>! q\<close>
 proof -
   have \<open>ptautology ((p \<^bold>\<longleftrightarrow>\<^sub>! p') \<^bold>\<longrightarrow>\<^sub>! (p \<^bold>\<longleftrightarrow>\<^sub>! q) \<^bold>\<longrightarrow>\<^sub>! (p' \<^bold>\<longleftrightarrow>\<^sub>! q))\<close>
     by (metis peval.simps(4-5))
   with PA1 have \<open>A \<turnstile>\<^sub>! (p \<^bold>\<longleftrightarrow>\<^sub>! p') \<^bold>\<longrightarrow>\<^sub>! (p \<^bold>\<longleftrightarrow>\<^sub>! q) \<^bold>\<longrightarrow>\<^sub>! (p' \<^bold>\<longleftrightarrow>\<^sub>! q)\<close> .
   then show ?thesis
     using assms PR1 by blast
 qed
 
 lemma K'_A2': \<open>A \<turnstile>\<^sub>! K\<^sub>! i (p \<^bold>\<longrightarrow>\<^sub>! q) \<^bold>\<longrightarrow>\<^sub>! K\<^sub>! i p \<^bold>\<longrightarrow>\<^sub>! K\<^sub>! i q\<close>
 proof -
   have \<open>A \<turnstile>\<^sub>! K\<^sub>! i p \<^bold>\<and>\<^sub>! K\<^sub>! i (p \<^bold>\<longrightarrow>\<^sub>! q) \<^bold>\<longrightarrow>\<^sub>! K\<^sub>! i q\<close>
     using PA2 by fast
   moreover have \<open>A \<turnstile>\<^sub>! (P \<^bold>\<and>\<^sub>! Q \<^bold>\<longrightarrow>\<^sub>! R) \<^bold>\<longrightarrow>\<^sub>! (Q \<^bold>\<longrightarrow>\<^sub>! P \<^bold>\<longrightarrow>\<^sub>! R)\<close> for P Q R
     by (simp add: PA1)
   ultimately show ?thesis
     using PR1 by fast
 qed
 
 lemma K'_map:
   assumes \<open>A \<turnstile>\<^sub>! p \<^bold>\<longrightarrow>\<^sub>! q\<close>
   shows \<open>A \<turnstile>\<^sub>! K\<^sub>! i p \<^bold>\<longrightarrow>\<^sub>! K\<^sub>! i q\<close>
 proof -
   note \<open>A \<turnstile>\<^sub>! p \<^bold>\<longrightarrow>\<^sub>! q\<close>
   then have \<open>A \<turnstile>\<^sub>! K\<^sub>! i (p \<^bold>\<longrightarrow>\<^sub>! q)\<close>
     using PR2 by fast
   moreover have \<open>A \<turnstile>\<^sub>! K\<^sub>! i (p \<^bold>\<longrightarrow>\<^sub>! q) \<^bold>\<longrightarrow>\<^sub>! K\<^sub>! i p \<^bold>\<longrightarrow>\<^sub>! K\<^sub>! i q\<close>
     using K'_A2' by fast
   ultimately show ?thesis
     using PR1 by fast
 qed
 
 lemma ConI:
   assumes \<open>A \<turnstile>\<^sub>! p\<close> \<open>A \<turnstile>\<^sub>! q\<close>
   shows \<open>A \<turnstile>\<^sub>! p \<^bold>\<and>\<^sub>! q\<close>
 proof -
   have \<open>A \<turnstile>\<^sub>! p \<^bold>\<longrightarrow>\<^sub>! q \<^bold>\<longrightarrow>\<^sub>! p \<^bold>\<and>\<^sub>! q\<close>
     by (simp add: PA1)
   then show ?thesis
     using assms PR1 by blast
 qed
 
 lemma Iff_wk:
   assumes \<open>A \<turnstile>\<^sub>! p \<^bold>\<longleftrightarrow>\<^sub>! q\<close>
   shows \<open>A \<turnstile>\<^sub>! (r \<^bold>\<longrightarrow>\<^sub>! p) \<^bold>\<longleftrightarrow>\<^sub>! (r \<^bold>\<longrightarrow>\<^sub>! q)\<close>
 proof -
   have \<open>A \<turnstile>\<^sub>! (p \<^bold>\<longleftrightarrow>\<^sub>! q) \<^bold>\<longrightarrow>\<^sub>! ((r \<^bold>\<longrightarrow>\<^sub>! p) \<^bold>\<longleftrightarrow>\<^sub>! (r \<^bold>\<longrightarrow>\<^sub>! q))\<close>
     by (simp add: PA1)
   then show ?thesis
     using assms PR1 by blast
 qed
 
 lemma Iff_reduce':
   assumes \<open>static p\<close>
   shows \<open>A \<turnstile>\<^sub>! [r]\<^sub>! p \<^bold>\<longleftrightarrow>\<^sub>! reduce' r p\<close>
   using assms
 proof (induct p rule: pfm.induct)
   case FF
   then show ?case
     by (simp add: PFF)
 next
   case (Pro' x)
   then show ?case
     by (simp add: PPro)
 next
   case (Dis p q)
   then have \<open>A \<turnstile>\<^sub>! [r]\<^sub>! p \<^bold>\<or>\<^sub>! [r]\<^sub>! q \<^bold>\<longleftrightarrow>\<^sub>! reduce' r (p \<^bold>\<or>\<^sub>! q)\<close>
     using Iff_Dis by fastforce
   moreover have \<open>A \<turnstile>\<^sub>! ([r]\<^sub>! p \<^bold>\<or>\<^sub>! [r]\<^sub>! q) \<^bold>\<longleftrightarrow>\<^sub>! ([r]\<^sub>! (p \<^bold>\<or>\<^sub>! q))\<close>
     using PDis Iff_sym by fastforce
   ultimately show ?case
     using PA1 PR1 Iff_Iff by blast
 next
   case (Con p q)
   then have \<open>A \<turnstile>\<^sub>! [r]\<^sub>! p \<^bold>\<and>\<^sub>! [r]\<^sub>! q \<^bold>\<longleftrightarrow>\<^sub>! reduce' r (p \<^bold>\<and>\<^sub>! q)\<close>
     using Iff_Con by fastforce
   moreover have \<open>A \<turnstile>\<^sub>! ([r]\<^sub>! p \<^bold>\<and>\<^sub>! [r]\<^sub>! q) \<^bold>\<longleftrightarrow>\<^sub>! ([r]\<^sub>! (p \<^bold>\<and>\<^sub>! q))\<close>
     using PCon Iff_sym by fastforce
   ultimately show ?case
     using PA1 PR1 Iff_Iff by blast
 next
   case (Imp p q)
   then have \<open>A \<turnstile>\<^sub>! ([r]\<^sub>! p \<^bold>\<longrightarrow>\<^sub>! [r]\<^sub>! q) \<^bold>\<longleftrightarrow>\<^sub>! reduce' r (p \<^bold>\<longrightarrow>\<^sub>! q)\<close>
     using Iff_Imp by fastforce
   moreover have \<open>A \<turnstile>\<^sub>! ([r]\<^sub>! p \<^bold>\<longrightarrow>\<^sub>! [r]\<^sub>! q) \<^bold>\<longleftrightarrow>\<^sub>! ([r]\<^sub>! (p \<^bold>\<longrightarrow>\<^sub>! q))\<close>
     using PImp Iff_sym by fastforce
   ultimately show ?case
     using PA1 PR1 Iff_Iff by blast
 next
   case (K' i p)
   then have \<open>A \<turnstile>\<^sub>! [r]\<^sub>! p \<^bold>\<longleftrightarrow>\<^sub>! reduce' r p\<close>
     by simp
   then have \<open>A \<turnstile>\<^sub>! K\<^sub>! i ([r]\<^sub>! p) \<^bold>\<longleftrightarrow>\<^sub>! K\<^sub>! i (reduce' r p)\<close>
     using K'_map ConE ConI by metis
   moreover have \<open>A \<turnstile>\<^sub>! [r]\<^sub>! K\<^sub>! i p \<^bold>\<longleftrightarrow>\<^sub>! r \<^bold>\<longrightarrow>\<^sub>! K\<^sub>! i ([r]\<^sub>! p)\<close>
     using PK .
   ultimately have \<open>A \<turnstile>\<^sub>! [r]\<^sub>! K\<^sub>! i p \<^bold>\<longleftrightarrow>\<^sub>! r \<^bold>\<longrightarrow>\<^sub>! K\<^sub>! i (reduce' r p)\<close>
     by (meson Iff_Iff Iff_sym Iff_wk)
   then show ?case
     by simp
 next
   case (Ann r p)
   then show ?case
     by simp
 qed
 
 lemma Iff_Ann1:
   assumes r: \<open>A \<turnstile>\<^sub>! r \<^bold>\<longleftrightarrow>\<^sub>! r'\<close> and \<open>static p\<close>
   shows \<open>A \<turnstile>\<^sub>! [r]\<^sub>! p \<^bold>\<longleftrightarrow>\<^sub>! [r']\<^sub>! p\<close>
   using assms(2-)
 proof (induct p)
   case FF
   have \<open>A \<turnstile>\<^sub>! (r \<^bold>\<longleftrightarrow>\<^sub>! r') \<^bold>\<longrightarrow>\<^sub>! ((r \<^bold>\<longrightarrow>\<^sub>! \<^bold>\<bottom>\<^sub>!) \<^bold>\<longleftrightarrow>\<^sub>! (r' \<^bold>\<longrightarrow>\<^sub>! \<^bold>\<bottom>\<^sub>!))\<close>
     by (auto intro: PA1)
   then have \<open>A \<turnstile>\<^sub>! (r \<^bold>\<longrightarrow>\<^sub>! \<^bold>\<bottom>\<^sub>!) \<^bold>\<longleftrightarrow>\<^sub>! (r' \<^bold>\<longrightarrow>\<^sub>! \<^bold>\<bottom>\<^sub>!)\<close>
     using r PR1 by blast
   then show ?case
     by (meson PFF Iff_Iff Iff_sym)
 next
   case (Pro' x)
   have \<open>A \<turnstile>\<^sub>! (r \<^bold>\<longleftrightarrow>\<^sub>! r') \<^bold>\<longrightarrow>\<^sub>! ((r \<^bold>\<longrightarrow>\<^sub>! Pro\<^sub>! x) \<^bold>\<longleftrightarrow>\<^sub>! (r' \<^bold>\<longrightarrow>\<^sub>! Pro\<^sub>! x))\<close>
     by (auto intro: PA1)
   then have \<open>A \<turnstile>\<^sub>! (r \<^bold>\<longrightarrow>\<^sub>! Pro\<^sub>! x) \<^bold>\<longleftrightarrow>\<^sub>! (r' \<^bold>\<longrightarrow>\<^sub>! Pro\<^sub>! x)\<close>
     using r PR1 by blast
   then show ?case
     by (meson PPro Iff_Iff Iff_sym)
 next
   case (Dis p q)
   then have \<open>A \<turnstile>\<^sub>! [r]\<^sub>! p \<^bold>\<or>\<^sub>! [r]\<^sub>! q \<^bold>\<longleftrightarrow>\<^sub>! [r']\<^sub>! p \<^bold>\<or>\<^sub>! [r']\<^sub>! q\<close>
     by (simp add: Iff_Dis)
   then show ?case
     by (meson PDis Iff_Iff Iff_sym)
 next
   case (Con p q)
   then have \<open>A \<turnstile>\<^sub>! [r]\<^sub>! p \<^bold>\<and>\<^sub>! [r]\<^sub>! q \<^bold>\<longleftrightarrow>\<^sub>! [r']\<^sub>! p \<^bold>\<and>\<^sub>! [r']\<^sub>! q\<close>
     by (simp add: Iff_Con)
   then show ?case
     by (meson PCon Iff_Iff Iff_sym)
 next
   case (Imp p q)
   then have \<open>A \<turnstile>\<^sub>! ([r]\<^sub>! p \<^bold>\<longrightarrow>\<^sub>! [r]\<^sub>! q) \<^bold>\<longleftrightarrow>\<^sub>! ([r']\<^sub>! p \<^bold>\<longrightarrow>\<^sub>! [r']\<^sub>! q)\<close>
     by (simp add: Iff_Imp)
   then show ?case
     by (meson PImp Iff_Iff Iff_sym)
 next
   case (K' i p)
   then have \<open>A \<turnstile>\<^sub>! [r]\<^sub>! p \<^bold>\<longleftrightarrow>\<^sub>! [r']\<^sub>! p\<close>
     by simp
   then have \<open>A \<turnstile>\<^sub>! K\<^sub>! i ([r]\<^sub>! p) \<^bold>\<longleftrightarrow>\<^sub>! K\<^sub>! i ([r']\<^sub>! p)\<close>
     using K'_map ConE ConI by metis
   then show ?case
     by (meson Iff_Iff Iff_Imp Iff_sym PK r)
 next
   case (Ann s p)
   then show ?case
     by simp
 qed
 
 lemma Iff_Ann2:
   assumes \<open>A \<turnstile>\<^sub>! p \<^bold>\<longleftrightarrow>\<^sub>! p'\<close>
   shows \<open>A \<turnstile>\<^sub>! [r]\<^sub>! p \<^bold>\<longleftrightarrow>\<^sub>! [r]\<^sub>! p'\<close>
   using assms PAnn ConE ConI PImp PR1 by metis
 
 lemma Iff_reduce: \<open>A \<turnstile>\<^sub>! p \<^bold>\<longleftrightarrow>\<^sub>! reduce p\<close>
 proof (induct p)
   case (Dis p q)
   then show ?case
     by (simp add: Iff_Dis)
 next
   case (Con p q)
   then show ?case
     by (simp add: Iff_Con)
 next
   case (Imp p q)
   then show ?case
     by (simp add: Iff_Imp)
 next
   case (K' i p)
   have
     \<open>A \<turnstile>\<^sub>! K\<^sub>! i p \<^bold>\<longrightarrow>\<^sub>! K\<^sub>! i (reduce p)\<close>
     \<open>A \<turnstile>\<^sub>! K\<^sub>! i (reduce p) \<^bold>\<longrightarrow>\<^sub>! K\<^sub>! i p\<close>
     using K' K'_map ConE by fast+
   then have \<open>A \<turnstile>\<^sub>! K\<^sub>! i p \<^bold>\<longleftrightarrow>\<^sub>! K\<^sub>! i (reduce p)\<close>
     using ConI by blast
   then show ?case
     by simp
 next
   case (Ann r p)
   have \<open>A \<turnstile>\<^sub>! [reduce r]\<^sub>! reduce p \<^bold>\<longleftrightarrow>\<^sub>! reduce' (reduce r) (reduce p)\<close>
     using Iff_reduce' static_reduce by blast
   moreover have \<open>A \<turnstile>\<^sub>! [r]\<^sub>! reduce p \<^bold>\<longleftrightarrow>\<^sub>! [reduce r]\<^sub>! reduce p\<close>
     using Ann(1) Iff_Ann1 static_reduce by blast
   ultimately have \<open>A \<turnstile>\<^sub>! [r]\<^sub>! reduce p \<^bold>\<longleftrightarrow>\<^sub>! reduce' (reduce r) (reduce p)\<close>
     using Iff_Iff Iff_sym by blast
   moreover have \<open>A \<turnstile>\<^sub>! [r]\<^sub>! reduce p \<^bold>\<longleftrightarrow>\<^sub>! [r]\<^sub>! p\<close>
     by (meson Ann(2) static_reduce Iff_Ann2 Iff_sym)
   ultimately have \<open>A \<turnstile>\<^sub>! [r]\<^sub>! p \<^bold>\<longleftrightarrow>\<^sub>! reduce' (reduce r) (reduce p)\<close>
     using Iff_Iff by blast
   then show ?case
     by simp
 qed (simp_all add: PA1)
 
-theorem completeness\<^sub>P:
-  assumes \<open>valid\<^sub>! P p\<close> and \<open>valid P (lower (reduce p)) \<Longrightarrow> A o lift \<turnstile> lower (reduce p)\<close>
-  shows \<open>A \<turnstile>\<^sub>! p\<close>
+theorem strong_completeness\<^sub>P:
+  assumes \<open>valid\<^sub>! P G p\<close>
+    and \<open>valid P (lower ` reduce ` G) (lower (reduce p)) \<Longrightarrow>
+      \<exists>qs. set qs \<subseteq> lower ` reduce ` G \<and> (A o lift \<turnstile> qs \<^bold>\<leadsto> lower (reduce p))\<close>
+  shows \<open>\<exists>qs. set qs \<subseteq> G \<and> (A \<turnstile>\<^sub>! qs \<^bold>\<leadsto>\<^sub>! p)\<close>
 proof -
-  have \<open>valid\<^sub>! P (reduce p)\<close>
+  have \<open>valid\<^sub>! P (reduce ` G) (reduce p)\<close>
     using assms(1) reduce_semantics by fast
-  moreover have \<open>static (reduce p)\<close>
-    using static_reduce by fast
-  ultimately have \<open>A \<turnstile>\<^sub>! reduce p\<close>
-    using static_completeness assms(2) by blast
-  moreover have \<open>A \<turnstile>\<^sub>! (p \<^bold>\<longleftrightarrow>\<^sub>! reduce p)\<close>
+  moreover have \<open>static (reduce p)\<close> \<open>\<forall>q \<in> reduce ` G. static q\<close>
+    using static_reduce by fast+
+  ultimately have \<open>\<exists>qs. set qs \<subseteq> reduce ` G \<and> (A \<turnstile>\<^sub>! qs \<^bold>\<leadsto>\<^sub>! reduce p)\<close>
+    using assms(2) strong_static_completeness[where G=\<open>reduce ` G\<close> and p=\<open>reduce p\<close>] by presburger
+  then have \<open>\<exists>qs. set qs \<subseteq> G \<and> (A \<turnstile>\<^sub>! map reduce qs \<^bold>\<leadsto>\<^sub>! reduce p)\<close>
+    using set_map_inv by fast
+  then obtain qs where qs: \<open>set qs \<subseteq> G\<close> and \<open>A \<turnstile>\<^sub>! map reduce qs \<^bold>\<leadsto>\<^sub>! reduce p\<close>
+    by blast
+  then have \<open>A \<turnstile>\<^sub>! reduce (qs \<^bold>\<leadsto>\<^sub>! p)\<close>
+    using reduce_imply by metis
+  moreover have \<open>A \<turnstile>\<^sub>! (qs \<^bold>\<leadsto>\<^sub>! p) \<^bold>\<longleftrightarrow>\<^sub>! reduce (qs \<^bold>\<leadsto>\<^sub>! p)\<close>
     using Iff_reduce by blast
-  ultimately show ?thesis
+  ultimately have \<open>A \<turnstile>\<^sub>! qs \<^bold>\<leadsto>\<^sub>! p\<close>
     using ConE(2) PR1 by blast
+  then show ?thesis
+    using qs by blast
 qed
 
-corollary completeness\<^sub>P\<^sub>K:
-  assumes \<open>valid\<^sub>! (\<lambda>_. True) p\<close>
+corollary completeness\<^sub>P:
+  assumes \<open>valid\<^sub>! P {} p\<close> and \<open>\<And>p. valid P {} (lower p) \<Longrightarrow> A o lift \<turnstile> lower p\<close>
   shows \<open>A \<turnstile>\<^sub>! p\<close>
-  using assms completeness\<^sub>P[where P=\<open>\<lambda>_. True\<close>] completeness\<^sub>K by metis
+  using assms strong_completeness\<^sub>P[where P=P and G=\<open>{}\<close>] by simp
+
+corollary completeness\<^sub>P\<^sub>A:
+  assumes \<open>valid\<^sub>! (\<lambda>_. True) {} p\<close>
+  shows \<open>A \<turnstile>\<^sub>! p\<close>
+  using assms completeness\<^sub>P[where P=\<open>\<lambda>_. True\<close> and p=p] completeness\<^sub>A by blast
 
 section \<open>System PAL + K\<close>
 
 abbreviation SystemPK :: \<open>'i pfm \<Rightarrow> bool\<close> (\<open>\<turnstile>\<^sub>!\<^sub>K _\<close> [20] 20) where
   \<open>\<turnstile>\<^sub>!\<^sub>K p \<equiv> (\<lambda>_. False) \<turnstile>\<^sub>! p\<close>
 
 lemma soundness\<^sub>P\<^sub>K: \<open>\<turnstile>\<^sub>!\<^sub>K p \<Longrightarrow> w \<in> \<W> M \<Longrightarrow> M, w \<Turnstile>\<^sub>! p\<close>
   using soundness[where P=\<open>\<lambda>_. True\<close>] by metis
 
 abbreviation validPK (\<open>valid\<^sub>!\<^sub>K\<close>) where
   \<open>valid\<^sub>!\<^sub>K \<equiv> valid\<^sub>! (\<lambda>_. True)\<close>
 
-corollary
-  assumes \<open>valid\<^sub>!\<^sub>K p\<close>
+theorem strong_completeness\<^sub>P\<^sub>K:
+  assumes \<open>valid\<^sub>!\<^sub>K G p\<close>
+  shows \<open>\<exists>qs. set qs \<subseteq> G \<and> (\<turnstile>\<^sub>!\<^sub>K qs \<^bold>\<leadsto>\<^sub>! p)\<close>
+  using strong_completeness\<^sub>P assms strong_completeness\<^sub>K unfolding comp_apply .
+
+corollary completeness\<^sub>P\<^sub>K:
+  assumes \<open>valid\<^sub>!\<^sub>K {} p\<close>
   shows \<open>\<turnstile>\<^sub>!\<^sub>K p\<close>
-  using completeness\<^sub>P\<^sub>K assms .
+  using completeness\<^sub>P\<^sub>A assms .
 
-theorem main\<^sub>P\<^sub>K: \<open>valid\<^sub>!\<^sub>K p = (\<turnstile>\<^sub>!\<^sub>K p)\<close>
+theorem main\<^sub>P\<^sub>K: \<open>valid\<^sub>!\<^sub>K {} p = (\<turnstile>\<^sub>!\<^sub>K p)\<close>
   using soundness\<^sub>P\<^sub>K completeness\<^sub>P\<^sub>K by fast
 
 corollary
-  assumes \<open>valid\<^sub>!\<^sub>K p\<close> and \<open>w \<in> \<W> M\<close>
+  assumes \<open>valid\<^sub>!\<^sub>K {} p\<close> and \<open>w \<in> \<W> M\<close>
   shows \<open>M, w \<Turnstile>\<^sub>! p\<close>
   using assms soundness\<^sub>P\<^sub>K completeness\<^sub>P\<^sub>K by metis
 
 section \<open>System PAL + T\<close>
 
 text \<open>Also known as System PAL + M\<close>
 
 inductive AxPT :: \<open>'i pfm \<Rightarrow> bool\<close> where
   \<open>AxPT (K\<^sub>! i p \<^bold>\<longrightarrow>\<^sub>! p)\<close>
 
 abbreviation SystemPT :: \<open>'i pfm \<Rightarrow> bool\<close> (\<open>\<turnstile>\<^sub>!\<^sub>T _\<close> [20] 20) where
   \<open>\<turnstile>\<^sub>!\<^sub>T p \<equiv> AxPT \<turnstile>\<^sub>! p\<close>
 
 lemma soundness_AxPT: \<open>AxPT p \<Longrightarrow> reflexive M \<Longrightarrow> w \<in> \<W> M \<Longrightarrow> M, w \<Turnstile>\<^sub>! p\<close>
   unfolding reflexive_def by (induct p rule: AxPT.induct) simp
 
 lemma reflexive_restrict: \<open>reflexive M \<Longrightarrow> reflexive (restrict M p)\<close>
   unfolding reflexive_def by simp
 
 lemma soundness\<^sub>P\<^sub>T: \<open>\<turnstile>\<^sub>!\<^sub>T p \<Longrightarrow> reflexive M \<Longrightarrow> w \<in> \<W> M \<Longrightarrow> M, w \<Turnstile>\<^sub>! p\<close>
   using soundness[where A=AxPT and P=reflexive] soundness_AxPT reflexive_restrict by fastforce
 
 lemma AxT_AxPT: \<open>AxT = AxPT o lift\<close>
   unfolding comp_apply using lower_lift
   by (metis AxPT.simps AxT.simps lift.simps(5-6) lower.simps(5-6))
 
 abbreviation validPT (\<open>valid\<^sub>!\<^sub>T\<close>) where
   \<open>valid\<^sub>!\<^sub>T \<equiv> valid\<^sub>! reflexive\<close>
 
-lemma completeness\<^sub>P\<^sub>T:
-  assumes \<open>valid\<^sub>!\<^sub>T p\<close>
+theorem strong_completeness\<^sub>P\<^sub>T:
+  assumes \<open>valid\<^sub>!\<^sub>T G p\<close>
+  shows \<open>\<exists>qs. set qs \<subseteq> G \<and> (\<turnstile>\<^sub>!\<^sub>T qs \<^bold>\<leadsto>\<^sub>! p)\<close>
+  using strong_completeness\<^sub>P assms strong_completeness\<^sub>T unfolding AxT_AxPT .
+
+corollary completeness\<^sub>P\<^sub>T:
+  assumes \<open>valid\<^sub>!\<^sub>T {} p\<close>
   shows \<open>\<turnstile>\<^sub>!\<^sub>T p\<close>
-  using assms completeness\<^sub>P[where p=p] completeness\<^sub>T AxT_AxPT by metis
+  using assms strong_completeness\<^sub>P\<^sub>T[where G=\<open>{}\<close>] by auto
 
-theorem main\<^sub>P\<^sub>T: \<open>valid\<^sub>!\<^sub>T p \<longleftrightarrow> (\<turnstile>\<^sub>!\<^sub>T p)\<close>
+theorem main\<^sub>P\<^sub>T: \<open>valid\<^sub>!\<^sub>T {} p \<longleftrightarrow> (\<turnstile>\<^sub>!\<^sub>T p)\<close>
   using soundness\<^sub>P\<^sub>T completeness\<^sub>P\<^sub>T by fast
 
 corollary
   assumes \<open>reflexive M\<close> \<open>w \<in> \<W> M\<close>
-  shows \<open>valid\<^sub>!\<^sub>T p \<longrightarrow> M, w \<Turnstile>\<^sub>! p\<close>
+  shows \<open>valid\<^sub>!\<^sub>T {} p \<longrightarrow> M, w \<Turnstile>\<^sub>! p\<close>
   using assms soundness\<^sub>P\<^sub>T completeness\<^sub>P\<^sub>T by fast
 
-section \<open>System PKB\<close>
+section \<open>System PAL + KB\<close>
 
 inductive AxPB :: \<open>'i pfm \<Rightarrow> bool\<close> where
   \<open>AxPB (p \<^bold>\<longrightarrow>\<^sub>! K\<^sub>! i (L\<^sub>! i p))\<close>
 
 abbreviation SystemPKB :: \<open>'i pfm \<Rightarrow> bool\<close> (\<open>\<turnstile>\<^sub>!\<^sub>K\<^sub>B _\<close> [20] 20) where
   \<open>\<turnstile>\<^sub>!\<^sub>K\<^sub>B p \<equiv> AxPB \<turnstile>\<^sub>! p\<close>
 
 lemma soundness_AxPB: \<open>AxPB p \<Longrightarrow> symmetric M \<Longrightarrow> w \<in> \<W> M \<Longrightarrow> M, w \<Turnstile>\<^sub>! p\<close>
   unfolding symmetric_def by (induct p rule: AxPB.induct) auto
 
 lemma symmetric_restrict: \<open>symmetric M \<Longrightarrow> symmetric (restrict M p)\<close>
   unfolding symmetric_def by simp
 
 lemma soundness\<^sub>P\<^sub>K\<^sub>B: \<open>\<turnstile>\<^sub>!\<^sub>K\<^sub>B p \<Longrightarrow> symmetric M \<Longrightarrow> w \<in> \<W> M \<Longrightarrow> M, w \<Turnstile>\<^sub>! p\<close>
   using soundness[where A=AxPB and P=symmetric] soundness_AxPB symmetric_restrict by fastforce
 
 lemma AxB_AxPB: \<open>AxB = AxPB o lift\<close>
 proof
   fix p :: \<open>'i fm\<close>
   show \<open>AxB p = (AxPB \<circ> lift) p\<close>
     unfolding comp_apply using lower_lift
     by (smt (verit, best) AxB.simps AxPB.simps lift.simps(1, 5-6) lower.simps(5-6))
 qed
 
 abbreviation validPKB (\<open>valid\<^sub>!\<^sub>K\<^sub>B\<close>) where
   \<open>valid\<^sub>!\<^sub>K\<^sub>B \<equiv> valid\<^sub>! symmetric\<close>
 
-lemma completeness\<^sub>P\<^sub>K\<^sub>B:
-  assumes \<open>valid\<^sub>!\<^sub>K\<^sub>B p\<close>
+theorem strong_completeness\<^sub>P\<^sub>K\<^sub>B:
+  assumes \<open>valid\<^sub>!\<^sub>K\<^sub>B G p\<close>
+  shows \<open>\<exists>qs. set qs \<subseteq> G \<and> (\<turnstile>\<^sub>!\<^sub>K\<^sub>B qs \<^bold>\<leadsto>\<^sub>! p)\<close>
+  using strong_completeness\<^sub>P assms strong_completeness\<^sub>K\<^sub>B unfolding AxB_AxPB .
+
+corollary completeness\<^sub>P\<^sub>K\<^sub>B:
+  assumes \<open>valid\<^sub>!\<^sub>K\<^sub>B {} p\<close>
   shows \<open>\<turnstile>\<^sub>!\<^sub>K\<^sub>B p\<close>
-  using assms completeness\<^sub>P[where p=p] completeness\<^sub>K\<^sub>B AxB_AxPB by metis
+  using assms strong_completeness\<^sub>P\<^sub>K\<^sub>B[where G=\<open>{}\<close>] by auto
 
-theorem main\<^sub>P\<^sub>K\<^sub>B: \<open>valid\<^sub>!\<^sub>K\<^sub>B p \<longleftrightarrow> (\<turnstile>\<^sub>!\<^sub>K\<^sub>B p)\<close>
+theorem main\<^sub>P\<^sub>K\<^sub>B: \<open>valid\<^sub>!\<^sub>K\<^sub>B {} p \<longleftrightarrow> (\<turnstile>\<^sub>!\<^sub>K\<^sub>B p)\<close>
   using soundness\<^sub>P\<^sub>K\<^sub>B completeness\<^sub>P\<^sub>K\<^sub>B by fast
 
 corollary
   assumes \<open>symmetric M\<close> \<open>w \<in> \<W> M\<close>
-  shows \<open>valid\<^sub>!\<^sub>K\<^sub>B p \<longrightarrow> M, w \<Turnstile>\<^sub>! p\<close>
+  shows \<open>valid\<^sub>!\<^sub>K\<^sub>B {} p \<longrightarrow> M, w \<Turnstile>\<^sub>! p\<close>
   using assms soundness\<^sub>P\<^sub>K\<^sub>B completeness\<^sub>P\<^sub>K\<^sub>B by fast
 
-section \<open>System PK4\<close>
+section \<open>System PAL + K4\<close>
 
 inductive AxP4 :: \<open>'i pfm \<Rightarrow> bool\<close> where
   \<open>AxP4 (K\<^sub>! i p \<^bold>\<longrightarrow>\<^sub>! K\<^sub>! i (K\<^sub>! i p))\<close>
 
 abbreviation SystemPK4 :: \<open>'i pfm \<Rightarrow> bool\<close> (\<open>\<turnstile>\<^sub>!\<^sub>K\<^sub>4 _\<close> [20] 20) where
   \<open>\<turnstile>\<^sub>!\<^sub>K\<^sub>4 p \<equiv> AxP4 \<turnstile>\<^sub>! p\<close>
 
 lemma pos_introspection:
   assumes \<open>transitive M\<close> \<open>w \<in> \<W> M\<close>
   shows \<open>M, w \<Turnstile>\<^sub>! (K\<^sub>! i p \<^bold>\<longrightarrow>\<^sub>! K\<^sub>! i (K\<^sub>! i p))\<close>
 proof -
   { assume \<open>M, w \<Turnstile>\<^sub>! K\<^sub>! i p\<close>
     then have \<open>\<forall>v \<in> \<W> M \<inter> \<K> M i w. M, v \<Turnstile>\<^sub>! p\<close>
       by simp
     then have \<open>\<forall>v \<in> \<W> M \<inter> \<K> M i w. \<forall>u \<in> \<W> M \<inter> \<K> M i v. M, u \<Turnstile>\<^sub>! p\<close>
       using \<open>transitive M\<close> \<open>w \<in> \<W> M\<close> unfolding transitive_def by blast
     then have \<open>\<forall>v \<in> \<W> M \<inter> \<K> M i w. M, v \<Turnstile>\<^sub>! K\<^sub>! i p\<close>
       by simp
     then have \<open>M, w \<Turnstile>\<^sub>! K\<^sub>! i (K\<^sub>! i p)\<close>
       by simp }
   then show ?thesis
     by fastforce
 qed
 
 lemma soundness_AxP4: \<open>AxP4 p \<Longrightarrow> transitive M \<Longrightarrow> w \<in> \<W> M \<Longrightarrow> M, w \<Turnstile>\<^sub>! p\<close>
   by (induct p rule: AxP4.induct) (metis pos_introspection)
 
 lemma transitive_restrict: \<open>transitive M \<Longrightarrow> transitive (restrict M p)\<close>
   unfolding transitive_def
   by (metis (no_types, lifting) kripke.exhaust_sel kripke.inject mem_Collect_eq restrict.elims)
 
 lemma soundness\<^sub>P\<^sub>K\<^sub>4: \<open>\<turnstile>\<^sub>!\<^sub>K\<^sub>4 p \<Longrightarrow> transitive M \<Longrightarrow> w \<in> \<W> M \<Longrightarrow> M, w \<Turnstile>\<^sub>! p\<close>
   using soundness[where A=AxP4 and P=transitive] soundness_AxP4 transitive_restrict by fastforce
 
 lemma Ax4_AxP4: \<open>Ax4 = AxP4 o lift\<close>
 proof
   fix p :: \<open>'i fm\<close>
   show \<open>Ax4 p = (AxP4 \<circ> lift) p\<close>
     unfolding comp_apply using lower_lift
     by (smt (verit, best) Ax4.simps AxP4.simps lift.simps(1, 5-6) lower.simps(5-6))
 qed
 
 abbreviation validPK4 (\<open>valid\<^sub>!\<^sub>K\<^sub>4\<close>) where
   \<open>valid\<^sub>!\<^sub>K\<^sub>4 \<equiv> valid\<^sub>! transitive\<close>
 
-lemma completeness\<^sub>P\<^sub>K\<^sub>4:
-  assumes \<open>valid\<^sub>!\<^sub>K\<^sub>4 p\<close>
+theorem strong_completeness\<^sub>P\<^sub>K\<^sub>4:
+  assumes \<open>valid\<^sub>!\<^sub>K\<^sub>4 G p\<close>
+  shows \<open>\<exists>qs. set qs \<subseteq> G \<and> (\<turnstile>\<^sub>!\<^sub>K\<^sub>4 qs \<^bold>\<leadsto>\<^sub>! p)\<close>
+  using strong_completeness\<^sub>P assms strong_completeness\<^sub>K\<^sub>4 unfolding Ax4_AxP4 .
+
+corollary completeness\<^sub>P\<^sub>K\<^sub>4:
+  assumes \<open>valid\<^sub>!\<^sub>K\<^sub>4 {} p\<close>
   shows \<open>\<turnstile>\<^sub>!\<^sub>K\<^sub>4 p\<close>
-  using assms completeness\<^sub>P[where p=p] completeness\<^sub>K\<^sub>4 Ax4_AxP4 by metis
+  using assms strong_completeness\<^sub>P\<^sub>K\<^sub>4[where G=\<open>{}\<close>] by auto
 
-theorem main\<^sub>P\<^sub>K\<^sub>4: \<open>valid\<^sub>!\<^sub>K\<^sub>4 p \<longleftrightarrow> (\<turnstile>\<^sub>!\<^sub>K\<^sub>4 p)\<close>
+theorem main\<^sub>P\<^sub>K\<^sub>4: \<open>valid\<^sub>!\<^sub>K\<^sub>4 {} p \<longleftrightarrow> (\<turnstile>\<^sub>!\<^sub>K\<^sub>4 p)\<close>
   using soundness\<^sub>P\<^sub>K\<^sub>4 completeness\<^sub>P\<^sub>K\<^sub>4 by fast
 
 corollary
   assumes \<open>transitive M\<close> \<open>w \<in> \<W> M\<close>
-  shows \<open>valid\<^sub>!\<^sub>K\<^sub>4 p \<longrightarrow> M, w \<Turnstile>\<^sub>! p\<close>
+  shows \<open>valid\<^sub>!\<^sub>K\<^sub>4 {} p \<longrightarrow> M, w \<Turnstile>\<^sub>! p\<close>
   using assms soundness\<^sub>P\<^sub>K\<^sub>4 completeness\<^sub>P\<^sub>K\<^sub>4 by fast
 
-section \<open>System PS4\<close>
+section \<open>System PAL + S4\<close>
 
 abbreviation SystemPS4 :: \<open>'i pfm \<Rightarrow> bool\<close> (\<open>\<turnstile>\<^sub>!\<^sub>S\<^sub>4 _\<close> [20] 20) where
   \<open>\<turnstile>\<^sub>!\<^sub>S\<^sub>4 p \<equiv> AxPT \<oplus> AxP4 \<turnstile>\<^sub>! p\<close>
 
 lemma soundness_AxPT4: \<open>(AxPT \<oplus> AxP4) p \<Longrightarrow> refltrans M \<Longrightarrow> w \<in> \<W> M \<Longrightarrow> M, w \<Turnstile>\<^sub>! p\<close>
   using soundness_AxPT soundness_AxP4 by fast
 
 lemma refltrans_restrict: \<open>refltrans M \<Longrightarrow> refltrans (restrict M p)\<close>
   using reflexive_restrict transitive_restrict by blast
 
 lemma soundness\<^sub>P\<^sub>S\<^sub>4: \<open>\<turnstile>\<^sub>!\<^sub>S\<^sub>4 p \<Longrightarrow> reflexive M \<and> transitive M \<Longrightarrow> w \<in> \<W> M \<Longrightarrow> M, w \<Turnstile>\<^sub>! p\<close>
   using soundness[where A=\<open>AxPT \<oplus> AxP4\<close> and P=refltrans] soundness_AxPT4 refltrans_restrict
   by fastforce
 
 lemma AxT4_AxPT4: \<open>(AxT \<oplus> Ax4) = (AxPT \<oplus> AxP4) o lift\<close>
   using AxT_AxPT Ax4_AxP4 unfolding comp_apply by metis
 
 abbreviation validPS4 (\<open>valid\<^sub>!\<^sub>S\<^sub>4\<close>) where
   \<open>valid\<^sub>!\<^sub>S\<^sub>4 \<equiv> valid\<^sub>! refltrans\<close>
 
-lemma completeness\<^sub>P\<^sub>S\<^sub>4:
-  assumes \<open>valid\<^sub>!\<^sub>S\<^sub>4 p\<close>
+theorem strong_completeness\<^sub>P\<^sub>S\<^sub>4:
+  assumes \<open>valid\<^sub>!\<^sub>S\<^sub>4 G p\<close>
+  shows \<open>\<exists>qs. set qs \<subseteq> G \<and> (\<turnstile>\<^sub>!\<^sub>S\<^sub>4 qs \<^bold>\<leadsto>\<^sub>! p)\<close>
+  using strong_completeness\<^sub>P assms strong_completeness\<^sub>S\<^sub>4 unfolding AxT4_AxPT4 .
+
+corollary completeness\<^sub>P\<^sub>S\<^sub>4:
+  assumes \<open>valid\<^sub>!\<^sub>S\<^sub>4 {} p\<close>
   shows \<open>\<turnstile>\<^sub>!\<^sub>S\<^sub>4 p\<close>
-  using assms completeness\<^sub>P[where P=refltrans and p=p] completeness\<^sub>S\<^sub>4 AxT4_AxPT4
-  by (metis (mono_tags, lifting))
+  using assms strong_completeness\<^sub>P\<^sub>S\<^sub>4[where G=\<open>{}\<close>] by auto
 
-theorem main\<^sub>P\<^sub>S\<^sub>4: \<open>valid\<^sub>!\<^sub>S\<^sub>4 p \<longleftrightarrow> (\<turnstile>\<^sub>!\<^sub>S\<^sub>4 p)\<close>
+theorem main\<^sub>P\<^sub>S\<^sub>4: \<open>valid\<^sub>!\<^sub>S\<^sub>4 {} p \<longleftrightarrow> (\<turnstile>\<^sub>!\<^sub>S\<^sub>4 p)\<close>
   using soundness\<^sub>P\<^sub>S\<^sub>4 completeness\<^sub>P\<^sub>S\<^sub>4 by fast
 
 corollary
   assumes \<open>reflexive M\<close> \<open>transitive M\<close> \<open>w \<in> \<W> M\<close>
-  shows \<open>valid\<^sub>!\<^sub>S\<^sub>4 p \<longrightarrow> M, w \<Turnstile>\<^sub>! p\<close>
+  shows \<open>valid\<^sub>!\<^sub>S\<^sub>4 {} p \<longrightarrow> M, w \<Turnstile>\<^sub>! p\<close>
   using assms soundness\<^sub>P\<^sub>S\<^sub>4 completeness\<^sub>P\<^sub>S\<^sub>4 by fast
 
-section \<open>System PS5\<close>
+section \<open>System PAL + S5\<close>
 
 abbreviation SystemPS5 :: \<open>'i pfm \<Rightarrow> bool\<close> (\<open>\<turnstile>\<^sub>!\<^sub>S\<^sub>5 _\<close> [20] 20) where
   \<open>\<turnstile>\<^sub>!\<^sub>S\<^sub>5 p \<equiv> AxPT \<oplus> AxPB \<oplus> AxP4 \<turnstile>\<^sub>! p\<close>
 
 abbreviation AxPTB4 :: \<open>'i pfm \<Rightarrow> bool\<close> where
   \<open>AxPTB4 \<equiv> AxPT \<oplus> AxPB \<oplus> AxP4\<close>
 
 lemma soundness_AxPTB4: \<open>AxPTB4 p \<Longrightarrow> equivalence M \<Longrightarrow> w \<in> \<W> M \<Longrightarrow> M, w \<Turnstile>\<^sub>! p\<close>
   using soundness_AxPT soundness_AxPB soundness_AxP4 by fast
 
 lemma equivalence_restrict: \<open>equivalence M \<Longrightarrow> equivalence (restrict M p)\<close>
   using reflexive_restrict symmetric_restrict transitive_restrict by blast
 
 lemma soundness\<^sub>P\<^sub>S\<^sub>5: \<open>\<turnstile>\<^sub>!\<^sub>S\<^sub>5 p \<Longrightarrow> equivalence M \<Longrightarrow> w \<in> \<W> M \<Longrightarrow> M, w \<Turnstile>\<^sub>! p\<close>
   using soundness[where A=AxPTB4 and P=equivalence and M=M and w=w]
     soundness_AxPTB4 equivalence_restrict by fast
 
 lemma AxTB4_AxPTB4: \<open>AxTB4 = AxPTB4 o lift\<close>
   using AxT_AxPT AxB_AxPB Ax4_AxP4 unfolding comp_apply by metis
 
 abbreviation validPS5 (\<open>valid\<^sub>!\<^sub>S\<^sub>5\<close>) where
   \<open>valid\<^sub>!\<^sub>S\<^sub>5 \<equiv> valid\<^sub>! equivalence\<close>
 
-lemma completeness\<^sub>P\<^sub>S\<^sub>5:
-  assumes \<open>valid\<^sub>!\<^sub>S\<^sub>5 p\<close>
+theorem strong_completeness\<^sub>P\<^sub>S\<^sub>5:
+  assumes \<open>valid\<^sub>!\<^sub>S\<^sub>5 G p\<close>
+  shows \<open>\<exists>qs. set qs \<subseteq> G \<and> (\<turnstile>\<^sub>!\<^sub>S\<^sub>5 qs \<^bold>\<leadsto>\<^sub>! p)\<close>
+  using strong_completeness\<^sub>P assms strong_completeness\<^sub>S\<^sub>5 unfolding AxTB4_AxPTB4 .
+
+corollary completeness\<^sub>P\<^sub>S\<^sub>5:
+  assumes \<open>valid\<^sub>!\<^sub>S\<^sub>5 {} p\<close>
   shows \<open>\<turnstile>\<^sub>!\<^sub>S\<^sub>5 p\<close>
-  using assms completeness\<^sub>P[where P=equivalence and p=p] completeness\<^sub>S\<^sub>5 AxTB4_AxPTB4
-  by (metis (mono_tags, lifting))
+  using assms strong_completeness\<^sub>P\<^sub>S\<^sub>5[where G=\<open>{}\<close>] by auto
 
-theorem main\<^sub>P\<^sub>S\<^sub>5: \<open>valid\<^sub>!\<^sub>S\<^sub>5 p \<longleftrightarrow> (\<turnstile>\<^sub>!\<^sub>S\<^sub>5 p)\<close>
+theorem main\<^sub>P\<^sub>S\<^sub>5: \<open>valid\<^sub>!\<^sub>S\<^sub>5 {} p \<longleftrightarrow> (\<turnstile>\<^sub>!\<^sub>S\<^sub>5 p)\<close>
   using soundness\<^sub>P\<^sub>S\<^sub>5 completeness\<^sub>P\<^sub>S\<^sub>5 by fast
 
 corollary
   assumes \<open>reflexive M\<close> \<open>symmetric M\<close> \<open>transitive M\<close> \<open>w \<in> \<W> M\<close>
-  shows \<open>valid\<^sub>!\<^sub>S\<^sub>5 p \<longrightarrow> M, w \<Turnstile>\<^sub>! p\<close>
+  shows \<open>valid\<^sub>!\<^sub>S\<^sub>5 {} p \<longrightarrow> M, w \<Turnstile>\<^sub>! p\<close>
   using assms soundness\<^sub>P\<^sub>S\<^sub>5 completeness\<^sub>P\<^sub>S\<^sub>5 by fast
 
 end