(* Title: HOL/UNITY/Common
ID: $Id$
Author: Lawrence C Paulson, Cambridge University Computer Laboratory
Copyright 1998 University of Cambridge
Common Meeting Time example from Misra (1994)
The state is identified with the one variable in existence.
From Misra, "A Logic for Concurrent Programming" (1994), sections 5.1 and 13.1.
*)
Common = Union +
consts
ftime,gtime :: nat=>nat
rules
fmono "m <= n ==> ftime m <= ftime n"
gmono "m <= n ==> gtime m <= gtime n"
fasc "m <= ftime n"
gasc "m <= gtime n"
constdefs
common :: nat set
"common == {n. ftime n = n & gtime n = n}"
maxfg :: nat => nat set
"maxfg m == {t. t <= max (ftime m) (gtime m)}"
end