src/HOL/UNITY/Extend.thy
changeset 6297 5b9fbdfe22b7
child 6677 629b4b3d5bee
     1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/src/HOL/UNITY/Extend.thy	Wed Mar 03 10:32:35 1999 +0100
     1.3 @@ -0,0 +1,42 @@
     1.4 +(*  Title:      HOL/UNITY/Extend.thy
     1.5 +    ID:         $Id$
     1.6 +    Author:     Lawrence C Paulson, Cambridge University Computer Laboratory
     1.7 +    Copyright   1998  University of Cambridge
     1.8 +
     1.9 +Extending of state sets
    1.10 +  function f (forget)    maps the extended state to the original state
    1.11 +  function g (forgotten) maps the extended state to the "extending part"
    1.12 +*)
    1.13 +
    1.14 +Extend = Union + Comp +
    1.15 +
    1.16 +constdefs
    1.17 +
    1.18 +  extend_set :: "['a*'b => 'c, 'a set] => 'c set"
    1.19 +    "extend_set h A == h `` (A Times UNIV)"
    1.20 +
    1.21 +  extend_act :: "['a*'b => 'c, ('a*'a) set] => ('c * 'c) set"
    1.22 +    "extend_act h == (%act. UN (s,s'): act. UN y. {(h(s,y), h(s',y))})"
    1.23 +
    1.24 +  extend :: "['a*'b => 'c, 'a program] => 'c program"
    1.25 +    "extend h F == mk_program (extend_set h (Init F),
    1.26 +			       extend_act h `` Acts F)"
    1.27 +
    1.28 +locale Extend =
    1.29 +  fixes 
    1.30 +    f       :: 'c => 'a
    1.31 +    g       :: 'c => 'b
    1.32 +    h       :: "'a*'b => 'c"    (*isomorphism between 'a * 'b and 'c *)
    1.33 +    slice   :: ['c set, 'b] => 'a set
    1.34 +    f_act   :: "('c * 'c) set => ('a*'a) set"
    1.35 +
    1.36 +  assumes
    1.37 +    inj_h  "inj h"
    1.38 +    surj_h "surj h"
    1.39 +  defines
    1.40 +    f_def       "f z == fst (inv h z)"
    1.41 +    g_def       "g z == snd (inv h z)"
    1.42 +    slice_def   "slice Z y == {x. h(x,y) : Z}"
    1.43 +    f_act_def   "f_act act == (%(z,z'). (f z, f z')) `` act"
    1.44 +
    1.45 +end