| author | wenzelm |
| Mon, 08 Oct 2007 18:13:10 +0200 | |
| changeset 24911 | 4efb68e5576d |
| parent 21404 | eb85850d3eb7 |
| child 26438 | 090ced251009 |
| permissions | -rw-r--r-- |
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2841
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Added "discrete" CPOs and modified IMP to use those rather than "lift"
nipkow
parents:
2798
diff
changeset
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(* Title: HOLCF/IMP/Denotational.thy |
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ID: $Id$ |
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Author: Tobias Nipkow and Robert Sandner, TUM |
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Copyright 1996 TUM |
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*) |
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header "Denotational Semantics of Commands in HOLCF" |
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theory Denotational imports HOLCF Natural begin |
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subsection "Definition" |
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definition |
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more robust syntax for definition/abbreviation/notation;
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dlift :: "(('a::type) discr -> 'b::pcpo) => ('a lift -> 'b)" where
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"dlift f = (LAM x. case x of UU => UU | Def y => f\<cdot>(Discr y))" |
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2841
c2508f4ab739
Added "discrete" CPOs and modified IMP to use those rather than "lift"
nipkow
parents:
2798
diff
changeset
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c2508f4ab739
Added "discrete" CPOs and modified IMP to use those rather than "lift"
nipkow
parents:
2798
diff
changeset
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consts D :: "com => state discr -> state lift" |
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primrec |
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"D(\<SKIP>) = (LAM s. Def(undiscr s))" |
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"D(X :== a) = (LAM s. Def((undiscr s)[X \<mapsto> a(undiscr s)]))" |
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2841
c2508f4ab739
Added "discrete" CPOs and modified IMP to use those rather than "lift"
nipkow
parents:
2798
diff
changeset
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"D(c0 ; c1) = (dlift(D c1) oo (D c0))" |
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"D(\<IF> b \<THEN> c1 \<ELSE> c2) = |
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(LAM s. if b (undiscr s) then (D c1)\<cdot>s else (D c2)\<cdot>s)" |
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"D(\<WHILE> b \<DO> c) = |
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fix\<cdot>(LAM w s. if b (undiscr s) then (dlift w)\<cdot>((D c)\<cdot>s) |
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2841
c2508f4ab739
Added "discrete" CPOs and modified IMP to use those rather than "lift"
nipkow
parents:
2798
diff
changeset
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else Def(undiscr s))" |
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subsection |
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"Equivalence of Denotational Semantics in HOLCF and Evaluation Semantics in HOL" |
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lemma dlift_Def [simp]: "dlift f\<cdot>(Def x) = f\<cdot>(Discr x)" |
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by (simp add: dlift_def) |
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lemma cont_dlift [iff]: "cont (%f. dlift f)" |
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by (simp add: dlift_def) |
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lemma dlift_is_Def [simp]: |
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"(dlift f\<cdot>l = Def y) = (\<exists>x. l = Def x \<and> f\<cdot>(Discr x) = Def y)" |
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by (simp add: dlift_def split: lift.split) |
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lemma eval_implies_D: "\<langle>c,s\<rangle> \<longrightarrow>\<^sub>c t ==> D c\<cdot>(Discr s) = (Def t)" |
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apply (induct set: evalc) |
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apply simp_all |
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apply (subst fix_eq) |
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apply simp |
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apply (subst fix_eq) |
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apply simp |
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done |
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lemma D_implies_eval: "!s t. D c\<cdot>(Discr s) = (Def t) --> \<langle>c,s\<rangle> \<longrightarrow>\<^sub>c t" |
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apply (induct c) |
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apply simp |
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apply simp |
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apply force |
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apply (simp (no_asm)) |
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apply force |
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apply (simp (no_asm)) |
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apply (rule fix_ind) |
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apply (fast intro!: adm_lemmas adm_chfindom ax_flat) |
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apply (simp (no_asm)) |
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apply (simp (no_asm)) |
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apply safe |
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apply fast |
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done |
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theorem D_is_eval: "(D c\<cdot>(Discr s) = (Def t)) = (\<langle>c,s\<rangle> \<longrightarrow>\<^sub>c t)" |
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by (fast elim!: D_implies_eval [rule_format] eval_implies_D) |
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end |