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(* Title: KAD is KAT
Author: Victor Gomes, Georg Struth
Maintainer: Victor Gomes <victor.gomes@cl.cam.ac.uk>
Georg Struth <g.struth@sheffield.ac.uk>
*)
section \<open>Bringing KAT Components into Scope of KAD\<close>
theory KAD_is_KAT
imports KAD.Antidomain_Semiring
KAT_and_DRA.KAT
"AVC_KAD/VC_KAD"
"AVC_KAT/VC_KAT"
begin
context antidomain_kleene_algebra
begin
text \<open>Every Kleene algebra with domain is a Kleene algebra with tests. This fact should eventually move into
the AFP KAD entry.\<close>
sublocale kat "(+)" "(\<cdot>)" "1" "0" "(\<le>)" "(<)" star antidomain_op
apply standard
apply simp
using a_d_mult_closure am_d_def apply auto[1]
using dpdz.dom_weakly_local apply auto[1]
using a_d_add_closure a_de_morgan by presburger
text \<open>The next statement links the wp operator with the Hoare triple.\<close>
lemma H_kat_to_kad: "H p x q \<longleftrightarrow> d p \<le> |x] (d q)"
using H_def addual.ars_r_def fbox_demodalisation3 by auto
end
lemma H_eq: "P \<subseteq> Id \<Longrightarrow> Q \<subseteq> Id \<Longrightarrow> rel_kat.H P X Q = rel_antidomain_kleene_algebra.H P X Q"
apply (simp add: rel_kat.H_def rel_antidomain_kleene_algebra.H_def)
apply (subgoal_tac "rel_antidomain_kleene_algebra.t P = Id \<inter> P")
apply (subgoal_tac "rel_antidomain_kleene_algebra.t Q = Id \<inter> Q")
apply simp
apply (auto simp: rel_ad_def)
done
no_notation VC_KAD.spec_sugar ("PRE _ _ POST _" [64,64,64] 63)
and VC_KAD.cond_sugar ("IF _ THEN _ ELSE _ FI" [64,64,64] 63)
and VC_KAD.gets ("_ ::= _" [70, 65] 61)
text \<open>Next we provide some syntactic sugar.\<close>
lemma H_from_kat: "PRE p x POST q = (\<lceil>p\<rceil> \<le> (rel_antidomain_kleene_algebra.fbox x) \<lceil>q\<rceil>)"
apply (subst H_eq)
apply (clarsimp simp add: p2r_def)
apply (clarsimp simp add: p2r_def)
apply (subst rel_antidomain_kleene_algebra.H_kat_to_kad)
apply (subgoal_tac "rel_antidomain_kleene_algebra.ads_d \<lceil>p\<rceil> = \<lceil>p\<rceil>")
apply (subgoal_tac "rel_antidomain_kleene_algebra.ads_d \<lceil>q\<rceil> = \<lceil>q\<rceil>")
apply simp
apply (auto simp: rel_antidomain_kleene_algebra.ads_d_def rel_ad_def p2r_def)
done
lemma cond_iff: "rel_kat.ifthenelse \<lceil>P\<rceil> X Y = rel_antidomain_kleene_algebra.cond \<lceil>P\<rceil> X Y"
by (auto simp: rel_kat.ifthenelse_def rel_antidomain_kleene_algebra.cond_def)
lemma gets_iff: "v ::= e = VC_KAD.gets v e"
by (auto simp: VC_KAT.gets_def VC_KAD.gets_def)
text \<open>Finally we present two examples to test the integration.\<close>
lemma maximum:
"PRE (\<lambda>s:: nat store. True)
(IF (\<lambda>s. s ''x'' \<ge> s ''y'')
THEN (''z'' ::= (\<lambda>s. s ''x''))
ELSE (''z'' ::= (\<lambda>s. s ''y''))
FI)
POST (\<lambda>s. s ''z'' = max (s ''x'') (s ''y''))"
by (simp only: sH_cond_iff H_assign_iff, auto)
lemma maximum2:
"PRE (\<lambda>s:: nat store. True)
(IF (\<lambda>s. s ''x'' \<ge> s ''y'')
THEN (''z'' ::= (\<lambda>s. s ''x''))
ELSE (''z'' ::= (\<lambda>s. s ''y''))
FI)
POST (\<lambda>s. s ''z'' = max (s ''x'') (s ''y''))"
apply (subst H_from_kat)
apply (subst cond_iff)
apply (subst gets_iff)
apply (subst gets_iff)
by auto
end