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
```