author | paulson |
Tue, 21 Sep 1999 11:09:24 +0200 | |
changeset 7546 | 36b26759147e |
parent 7537 | 875754b599df |
child 7826 | c6a8b73b6c2a |
permissions | -rw-r--r-- |
6297 | 1 |
(* Title: HOL/UNITY/Extend.thy |
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ID: $Id$ |
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Author: Lawrence C Paulson, Cambridge University Computer Laboratory |
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Copyright 1998 University of Cambridge |
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Extending of state sets |
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function f (forget) maps the extended state to the original state |
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function g (forgotten) maps the extended state to the "extending part" |
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*) |
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Extend = Guar + |
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constdefs |
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good_map :: "['a*'b => 'c] => bool" |
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"good_map h == surj h & (ALL x y. fst (inv h (h (x,y))) = x)" |
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(*Using the locale constant "f", this is f (h (x,y))) = x*) |
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extend_set :: "['a*'b => 'c, 'a set] => 'c set" |
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"extend_set h A == h `` (A Times UNIV)" |
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project_set :: "['a*'b => 'c, 'c set] => 'a set" |
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"project_set h C == {x. EX y. h(x,y) : C}" |
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extend_act :: "['a*'b => 'c, ('a*'a) set] => ('c*'c) set" |
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"extend_act h act == UN (s,s'): act. UN y. {(h(s,y), h(s',y))}" |
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(*Argument C allows weak safety laws to be projected*) |
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project_act :: "['c set, 'a*'b => 'c, ('c*'c) set] => ('a*'a) set" |
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"project_act C h act == |
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36b26759147e
project_act no longer has a special case to allow identity actions
paulson
parents:
7537
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changeset
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{(x,x'). EX y y'. (h(x,y), h(x',y')) : act & (h(x,y) : C)}" |
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extend :: "['a*'b => 'c, 'a program] => 'c program" |
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"extend h F == mk_program (extend_set h (Init F), |
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extend_act h `` Acts F)" |
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project :: "['c set, 'a*'b => 'c, 'c program] => 'a program" |
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"project C h F == mk_program (project_set h (Init F), |
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project_act C h `` Acts F)" |
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locale Extend = |
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fixes |
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f :: 'c => 'a |
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g :: 'c => 'b |
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h :: "'a*'b => 'c" (*isomorphism between 'a * 'b and 'c *) |
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slice :: ['c set, 'b] => 'a set |
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assumes |
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good_h "good_map h" |
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defines |
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f_def "f z == fst (inv h z)" |
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g_def "g z == snd (inv h z)" |
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slice_def "slice Z y == {x. h(x,y) : Z}" |
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end |