Added P&P&Q = P&Q and P|P|Q = P|Q.
(* Title: HOL/IOA/example/Action.ML
ID: $Id$
Author: Tobias Nipkow & Konrad Slind
Copyright 1994 TU Muenchen
Derived rules for actions
*)
goal Action.thy "!!x. x = y ==> action_case a b c d e f g x = \
\ action_case a b c d e f g y";
by (Asm_simp_tac 1);
Addcongs [result()];