author | Christian Sternagel |
Thu, 30 Aug 2012 15:44:03 +0900 | |
changeset 49093 | fdc301f592c4 |
parent 48759 | ff570720ba1c |
child 49095 | 7df19036392e |
permissions | -rw-r--r-- |
47613 | 1 |
(* Author: Tobias Nipkow *) |
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theory Abs_Int1 |
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imports Abs_State |
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begin |
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lemma le_iff_le_annos_zip: "C1 \<sqsubseteq> C2 \<longleftrightarrow> |
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(\<forall> (a1,a2) \<in> set(zip (annos C1) (annos C2)). a1 \<sqsubseteq> a2) \<and> strip C1 = strip C2" |
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by(induct C1 C2 rule: le_acom.induct) (auto simp: size_annos_same2) |
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lemma le_iff_le_annos: "C1 \<sqsubseteq> C2 \<longleftrightarrow> |
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strip C1 = strip C2 \<and> (\<forall> i<size(annos C1). annos C1 ! i \<sqsubseteq> annos C2 ! i)" |
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by(auto simp add: le_iff_le_annos_zip set_zip) (metis size_annos_same2) |
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lemma mono_fun_wt[simp]: "wt F X \<Longrightarrow> F \<sqsubseteq> G \<Longrightarrow> x : X \<Longrightarrow> fun F x \<sqsubseteq> fun G x" |
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by(simp add: mono_fun wt_st_def) |
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lemma wt_bot[simp]: "wt (bot c) (vars c)" |
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by(simp add: wt_acom_def bot_def) |
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lemma wt_acom_simps[simp]: "wt (SKIP {P}) X \<longleftrightarrow> wt P X" |
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"wt (x ::= e {P}) X \<longleftrightarrow> x : X \<and> vars e \<subseteq> X \<and> wt P X" |
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"wt (C1;C2) X \<longleftrightarrow> wt C1 X \<and> wt C2 X" |
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"wt (IF b THEN C1 ELSE C2 {P}) X \<longleftrightarrow> |
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vars b \<subseteq> X \<and> wt C1 X \<and> wt C2 X \<and> wt P X" |
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"wt ({I} WHILE b DO C {P}) X \<longleftrightarrow> |
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wt I X \<and> vars b \<subseteq> X \<and> wt C X \<and> wt P X" |
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by(auto simp add: wt_acom_def) |
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lemma wt_post[simp]: "wt c X \<Longrightarrow> wt (post c) X" |
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by(induction c)(auto simp: wt_acom_def) |
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lemma lpfp_inv: |
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assumes "lpfp f x0 = Some x" and "\<And>x. P x \<Longrightarrow> P(f x)" and "P(bot x0)" |
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shows "P x" |
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using assms unfolding lpfp_def pfp_def |
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by (metis (lifting) while_option_rule) |
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subsection "Computable Abstract Interpretation" |
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text{* Abstract interpretation over type @{text st} instead of |
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functions. *} |
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context Gamma |
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begin |
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fun aval' :: "aexp \<Rightarrow> 'av st \<Rightarrow> 'av" where |
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"aval' (N n) S = num' n" | |
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"aval' (V x) S = fun S x" | |
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"aval' (Plus a1 a2) S = plus' (aval' a1 S) (aval' a2 S)" |
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lemma aval'_sound: "s : \<gamma>\<^isub>f S \<Longrightarrow> vars a \<subseteq> dom S \<Longrightarrow> aval a s : \<gamma>(aval' a S)" |
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by (induction a) (auto simp: gamma_num' gamma_plus' \<gamma>_st_def) |
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end |
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text{* The for-clause (here and elsewhere) only serves the purpose of fixing |
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the name of the type parameter @{typ 'av} which would otherwise be renamed to |
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@{typ 'a}. *} |
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locale Abs_Int = Gamma where \<gamma>=\<gamma> for \<gamma> :: "'av::SL_top \<Rightarrow> val set" |
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begin |
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fun step' :: "'av st option \<Rightarrow> 'av st option acom \<Rightarrow> 'av st option acom" where |
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"step' S (SKIP {P}) = (SKIP {S})" | |
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"step' S (x ::= e {P}) = |
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x ::= e {case S of None \<Rightarrow> None | Some S \<Rightarrow> Some(update S x (aval' e S))}" | |
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"step' S (C1; C2) = step' S C1; step' (post C1) C2" | |
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"step' S (IF b THEN C1 ELSE C2 {P}) = |
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(IF b THEN step' S C1 ELSE step' S C2 {post C1 \<squnion> post C2})" | |
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"step' S ({Inv} WHILE b DO C {P}) = |
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{S \<squnion> post C} WHILE b DO step' Inv C {Inv}" |
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definition AI :: "com \<Rightarrow> 'av st option acom option" where |
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"AI c = lpfp (step' (top c)) c" |
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lemma strip_step'[simp]: "strip(step' S C) = strip C" |
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by(induct C arbitrary: S) (simp_all add: Let_def) |
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text{* Soundness: *} |
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lemma in_gamma_update: |
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"\<lbrakk> s : \<gamma>\<^isub>f S; i : \<gamma> a \<rbrakk> \<Longrightarrow> s(x := i) : \<gamma>\<^isub>f(update S x a)" |
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by(simp add: \<gamma>_st_def) |
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theorem step_preserves_le: |
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"\<lbrakk> S \<subseteq> \<gamma>\<^isub>o S'; C \<le> \<gamma>\<^isub>c C'; wt C' X; wt S' X \<rbrakk> \<Longrightarrow> step S C \<le> \<gamma>\<^isub>c (step' S' C')" |
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proof(induction C arbitrary: C' S S') |
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case SKIP thus ?case by(auto simp:SKIP_le map_acom_SKIP) |
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next |
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case Assign thus ?case |
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by(fastforce simp: Assign_le map_acom_Assign wt_st_def |
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intro: aval'_sound in_gamma_update split: option.splits) |
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next |
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case Seq thus ?case apply (auto simp: Seq_le map_acom_Seq) |
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by (metis le_post post_map_acom wt_post) |
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next |
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case (If b C1 C2 P) |
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then obtain C1' C2' P' where |
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"C' = IF b THEN C1' ELSE C2' {P'}" |
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"P \<subseteq> \<gamma>\<^isub>o P'" "C1 \<le> \<gamma>\<^isub>c C1'" "C2 \<le> \<gamma>\<^isub>c C2'" |
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by (fastforce simp: If_le map_acom_If) |
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moreover from this(1) `wt C' X` have wt: "wt C1' X" "wt C2' X" |
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by simp_all |
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moreover have "post C1 \<subseteq> \<gamma>\<^isub>o(post C1' \<squnion> post C2')" |
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by (metis (no_types) `C1 \<le> \<gamma>\<^isub>c C1'` join_ge1 le_post mono_gamma_o order_trans post_map_acom wt wt_post) |
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moreover have "post C2 \<subseteq> \<gamma>\<^isub>o(post C1' \<squnion> post C2')" |
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by (metis (no_types) `C2 \<le> \<gamma>\<^isub>c C2'` join_ge2 le_post mono_gamma_o order_trans post_map_acom wt wt_post) |
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ultimately show ?case using `S \<subseteq> \<gamma>\<^isub>o S'` `wt S' X` |
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by (simp add: If.IH subset_iff) |
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next |
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case (While I b C1 P) |
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then obtain C1' I' P' where |
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"C' = {I'} WHILE b DO C1' {P'}" |
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"I \<subseteq> \<gamma>\<^isub>o I'" "P \<subseteq> \<gamma>\<^isub>o P'" "C1 \<le> \<gamma>\<^isub>c C1'" |
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by (fastforce simp: map_acom_While While_le) |
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moreover from this(1) `wt C' X` |
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have wt: "wt C1' X" "wt I' X" by simp_all |
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moreover note compat = `wt S' X` wt_post[OF wt(1)] |
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moreover have "S \<union> post C1 \<subseteq> \<gamma>\<^isub>o (S' \<squnion> post C1')" |
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using `S \<subseteq> \<gamma>\<^isub>o S'` le_post[OF `C1 \<le> \<gamma>\<^isub>c C1'`, simplified] |
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by (metis (no_types) join_ge1[OF compat] join_ge2[OF compat] le_sup_iff mono_gamma_o order_trans) |
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ultimately show ?case by (simp add: While.IH subset_iff) |
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qed |
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lemma wt_step'[simp]: |
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"\<lbrakk> wt C X; wt S X \<rbrakk> \<Longrightarrow> wt (step' S C) X" |
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proof(induction C arbitrary: S) |
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case Assign thus ?case |
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by(auto simp: wt_st_def update_def split: option.splits) |
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qed auto |
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theorem AI_sound: "AI c = Some C \<Longrightarrow> CS c \<le> \<gamma>\<^isub>c C" |
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proof(simp add: CS_def AI_def) |
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assume 1: "lpfp (step' (top c)) c = Some C" |
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have "wt C (vars c)" |
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by(rule lpfp_inv[where P = "%C. wt C (vars c)", OF 1 _ wt_bot]) |
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(erule wt_step'[OF _ wt_top]) |
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have 2: "step' (top c) C \<sqsubseteq> C" by(rule lpfpc_pfp[OF 1]) |
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have 3: "strip (\<gamma>\<^isub>c (step' (top c) C)) = c" |
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by(simp add: strip_lpfp[OF _ 1]) |
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48759
ff570720ba1c
Improved complete lattice formalisation - no more index set.
nipkow
parents:
47818
diff
changeset
|
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have "lfp c (step UNIV) \<le> \<gamma>\<^isub>c (step' (top c) C)" |
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proof(rule lfp_lowerbound[simplified,OF 3]) |
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show "step UNIV (\<gamma>\<^isub>c (step' (top c) C)) \<le> \<gamma>\<^isub>c (step' (top c) C)" |
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proof(rule step_preserves_le[OF _ _ `wt C (vars c)` wt_top]) |
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show "UNIV \<subseteq> \<gamma>\<^isub>o (top c)" by simp |
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show "\<gamma>\<^isub>c (step' (top c) C) \<le> \<gamma>\<^isub>c C" by(rule mono_gamma_c[OF 2]) |
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qed |
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qed |
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48759
ff570720ba1c
Improved complete lattice formalisation - no more index set.
nipkow
parents:
47818
diff
changeset
|
154 |
from this 2 show "lfp c (step UNIV) \<le> \<gamma>\<^isub>c C" |
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by (blast intro: mono_gamma_c order_trans) |
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qed |
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end |
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subsubsection "Monotonicity" |
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lemma le_join_disj: "wt y X \<Longrightarrow> wt (z::_::SL_top_wt) X \<Longrightarrow> x \<sqsubseteq> y \<or> x \<sqsubseteq> z \<Longrightarrow> x \<sqsubseteq> y \<squnion> z" |
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by (metis join_ge1 join_ge2 preord_class.le_trans) |
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locale Abs_Int_mono = Abs_Int + |
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assumes mono_plus': "a1 \<sqsubseteq> b1 \<Longrightarrow> a2 \<sqsubseteq> b2 \<Longrightarrow> plus' a1 a2 \<sqsubseteq> plus' b1 b2" |
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begin |
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lemma mono_aval': "S1 \<sqsubseteq> S2 \<Longrightarrow> wt S1 X \<Longrightarrow> vars e \<subseteq> X \<Longrightarrow> aval' e S1 \<sqsubseteq> aval' e S2" |
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by(induction e) (auto simp: le_st_def mono_plus' wt_st_def) |
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theorem mono_step': "wt S1 X \<Longrightarrow> wt S2 X \<Longrightarrow> wt C1 X \<Longrightarrow> wt C2 X \<Longrightarrow> |
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S1 \<sqsubseteq> S2 \<Longrightarrow> C1 \<sqsubseteq> C2 \<Longrightarrow> step' S1 C1 \<sqsubseteq> step' S2 C2" |
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apply(induction C1 C2 arbitrary: S1 S2 rule: le_acom.induct) |
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apply (auto simp: Let_def mono_aval' mono_post |
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le_join_disj le_join_disj[OF wt_post wt_post] |
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split: option.split) |
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done |
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lemma mono_step'_top: "wt c (vars c0) \<Longrightarrow> wt c' (vars c0) \<Longrightarrow> c \<sqsubseteq> c' \<Longrightarrow> step' (top c0) c \<sqsubseteq> step' (top c0) c'" |
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by (metis wt_top mono_step' preord_class.le_refl) |
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end |
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subsubsection "Termination" |
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abbreviation sqless (infix "\<sqsubset>" 50) where |
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"x \<sqsubset> y == x \<sqsubseteq> y \<and> \<not> y \<sqsubseteq> x" |
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lemma pfp_termination: |
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fixes x0 :: "'a::preord" and m :: "'a \<Rightarrow> nat" |
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assumes mono: "\<And>x y. I x \<Longrightarrow> I y \<Longrightarrow> x \<sqsubseteq> y \<Longrightarrow> f x \<sqsubseteq> f y" |
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and m: "\<And>x y. I x \<Longrightarrow> I y \<Longrightarrow> x \<sqsubset> y \<Longrightarrow> m x > m y" |
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and I: "\<And>x y. I x \<Longrightarrow> I(f x)" and "I x0" and "x0 \<sqsubseteq> f x0" |
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shows "EX x. pfp f x0 = Some x" |
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proof(simp add: pfp_def, rule wf_while_option_Some[where P = "%x. I x & x \<sqsubseteq> f x"]) |
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show "wf {(y,x). ((I x \<and> x \<sqsubseteq> f x) \<and> \<not> f x \<sqsubseteq> x) \<and> y = f x}" |
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by(rule wf_subset[OF wf_measure[of m]]) (auto simp: m I) |
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next |
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show "I x0 \<and> x0 \<sqsubseteq> f x0" using `I x0` `x0 \<sqsubseteq> f x0` by blast |
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next |
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fix x assume "I x \<and> x \<sqsubseteq> f x" thus "I(f x) \<and> f x \<sqsubseteq> f(f x)" |
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by (blast intro: I mono) |
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qed |
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lemma lpfp_termination: |
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fixes f :: "'a::preord option acom \<Rightarrow> 'a option acom" |
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and m :: "'a option acom \<Rightarrow> nat" and I :: "'a option acom \<Rightarrow> bool" |
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assumes "\<And>x y. I x \<Longrightarrow> I y \<Longrightarrow> x \<sqsubset> y \<Longrightarrow> m x > m y" |
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and "\<And>x y. I x \<Longrightarrow> I y \<Longrightarrow> x \<sqsubseteq> y \<Longrightarrow> f x \<sqsubseteq> f y" |
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and "\<And>x y. I x \<Longrightarrow> I(f x)" and "I(bot c)" |
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and "\<And>C. strip (f C) = strip C" |
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shows "\<exists>c'. lpfp f c = Some c'" |
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unfolding lpfp_def |
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by(fastforce intro: pfp_termination[where I=I and m=m] assms bot_least |
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simp: assms(5)) |
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locale Abs_Int_measure = |
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Abs_Int_mono where \<gamma>=\<gamma> for \<gamma> :: "'av::SL_top \<Rightarrow> val set" + |
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fixes m :: "'av \<Rightarrow> nat" |
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fixes h :: "nat" |
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assumes m1: "x \<sqsubseteq> y \<Longrightarrow> m x \<ge> m y" |
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assumes m2: "x \<sqsubset> y \<Longrightarrow> m x > m y" |
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assumes h: "m x \<le> h" |
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begin |
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definition "m_st S = (\<Sum> x \<in> dom S. m(fun S x))" |
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lemma m_st1: "S1 \<sqsubseteq> S2 \<Longrightarrow> m_st S1 \<ge> m_st S2" |
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proof(auto simp add: le_st_def m_st_def) |
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assume "\<forall>x\<in>dom S2. fun S1 x \<sqsubseteq> fun S2 x" |
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hence "\<forall>x\<in>dom S2. m(fun S1 x) \<ge> m(fun S2 x)" by (metis m1) |
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thus "(\<Sum>x\<in>dom S2. m (fun S2 x)) \<le> (\<Sum>x\<in>dom S2. m (fun S1 x))" |
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by (metis setsum_mono) |
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qed |
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lemma m_st2: "finite(dom S1) \<Longrightarrow> S1 \<sqsubset> S2 \<Longrightarrow> m_st S1 > m_st S2" |
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proof(auto simp add: le_st_def m_st_def) |
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assume "finite(dom S2)" and 0: "\<forall>x\<in>dom S2. fun S1 x \<sqsubseteq> fun S2 x" |
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hence 1: "\<forall>x\<in>dom S2. m(fun S1 x) \<ge> m(fun S2 x)" by (metis m1) |
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fix x assume "x \<in> dom S2" "\<not> fun S2 x \<sqsubseteq> fun S1 x" |
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hence 2: "\<exists>x\<in>dom S2. m(fun S1 x) > m(fun S2 x)" using 0 m2 by blast |
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from setsum_strict_mono_ex1[OF `finite(dom S2)` 1 2] |
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show "(\<Sum>x\<in>dom S2. m (fun S2 x)) < (\<Sum>x\<in>dom S2. m (fun S1 x))" . |
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qed |
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definition m_o :: "nat \<Rightarrow> 'av st option \<Rightarrow> nat" where |
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"m_o d opt = (case opt of None \<Rightarrow> h*d+1 | Some S \<Rightarrow> m_st S)" |
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definition m_c :: "'av st option acom \<Rightarrow> nat" where |
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"m_c c = (\<Sum>i<size(annos c). m_o (card(vars(strip c))) (annos c ! i))" |
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lemma m_st_h: "wt x X \<Longrightarrow> finite X \<Longrightarrow> m_st x \<le> h * card X" |
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by(simp add: wt_st_def m_st_def) |
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(metis nat_mult_commute of_nat_id setsum_bounded[OF h]) |
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lemma m_o1: "finite X \<Longrightarrow> wt o1 X \<Longrightarrow> wt o2 X \<Longrightarrow> |
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o1 \<sqsubseteq> o2 \<Longrightarrow> m_o (card X) o1 \<ge> m_o (card X) o2" |
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proof(induction o1 o2 rule: le_option.induct) |
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case 1 thus ?case by (simp add: m_o_def)(metis m_st1) |
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next |
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case 2 thus ?case |
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by(simp add: wt_option_def m_o_def le_SucI m_st_h split: option.splits) |
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next |
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case 3 thus ?case by simp |
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qed |
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lemma m_o2: "finite X \<Longrightarrow> wt o1 X \<Longrightarrow> wt o2 X \<Longrightarrow> |
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o1 \<sqsubset> o2 \<Longrightarrow> m_o (card X) o1 > m_o (card X) o2" |
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proof(induction o1 o2 rule: le_option.induct) |
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case 1 thus ?case by (simp add: m_o_def wt_st_def m_st2) |
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next |
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case 2 thus ?case |
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by(auto simp add: m_o_def le_imp_less_Suc m_st_h) |
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next |
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case 3 thus ?case by simp |
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qed |
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lemma m_c2: "wt c1 (vars(strip c1)) \<Longrightarrow> wt c2 (vars(strip c2)) \<Longrightarrow> |
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c1 \<sqsubset> c2 \<Longrightarrow> m_c c1 > m_c c2" |
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proof(auto simp add: le_iff_le_annos m_c_def size_annos_same[of c1 c2] wt_acom_def) |
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let ?X = "vars(strip c2)" |
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let ?n = "card ?X" |
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assume V1: "\<forall>a\<in>set(annos c1). wt a ?X" |
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and V2: "\<forall>a\<in>set(annos c2). wt a ?X" |
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and strip_eq: "strip c1 = strip c2" |
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and 0: "\<forall>i<size(annos c2). annos c1 ! i \<sqsubseteq> annos c2 ! i" |
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hence 1: "\<forall>i<size(annos c2). m_o ?n (annos c1 ! i) \<ge> m_o ?n (annos c2 ! i)" |
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by (auto simp: all_set_conv_all_nth) |
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(metis finite_cvars m_o1 size_annos_same2) |
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fix i assume "i < size(annos c2)" "\<not> annos c2 ! i \<sqsubseteq> annos c1 ! i" |
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hence "m_o ?n (annos c1 ! i) > m_o ?n (annos c2 ! i)" (is "?P i") |
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by(metis m_o2[OF finite_cvars] V1 V2 strip_eq nth_mem size_annos_same 0) |
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hence 2: "\<exists>i < size(annos c2). ?P i" using `i < size(annos c2)` by blast |
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299 |
show "(\<Sum>i<size(annos c2). m_o ?n (annos c2 ! i)) |
|
300 |
< (\<Sum>i<size(annos c2). m_o ?n (annos c1 ! i))" |
|
301 |
apply(rule setsum_strict_mono_ex1) using 1 2 by (auto) |
|
302 |
qed |
|
303 |
||
304 |
lemma AI_Some_measure: "\<exists>C. AI c = Some C" |
|
305 |
unfolding AI_def |
|
306 |
apply(rule lpfp_termination[where I = "%C. strip C = c \<and> wt C (vars c)" |
|
307 |
and m="m_c"]) |
|
308 |
apply(simp_all add: m_c2 mono_step'_top) |
|
309 |
done |
|
310 |
||
311 |
end |
|
312 |
||
313 |
end |