(* Title: HOL/UNITY/Union.thy
ID: $Id$
Author: Lawrence C Paulson, Cambridge University Computer Laboratory
Copyright 1998 University of Cambridge
Unions of programs
From Misra's Chapter 5: Asynchronous Compositions of Programs
*)
Union = SubstAx + FP +
constdefs
JOIN :: ['a set, 'a => 'b program] => 'b program
"JOIN I F == mk_program (INT i:I. Init (F i), UN i:I. Acts (F i))"
Join :: ['a program, 'a program] => 'a program (infixl 65)
"F Join G == mk_program (Init F Int Init G, Acts F Un Acts G)"
SKIP :: 'a program
"SKIP == mk_program (UNIV, {})"
Diff :: "['a program, ('a * 'a)set set] => 'a program"
"Diff F acts == mk_program (Init F, Acts F - acts)"
(*The set of systems that regard "f" as local to F*)
localTo :: ['a => 'b, 'a program] => 'a program set (infixl 80)
"f localTo F == {G. ALL z. Diff G (Acts F) : stable {s. f s = z}}"
syntax
"@JOIN" :: [pttrn, 'a set, 'b set] => 'b set ("(3JN _:_./ _)" 10)
translations
"JN x:A. B" == "JOIN A (%x. B)"
end