clasohm@0: (*  Title: 	HOL/gfp.thy
clasohm@0:     ID:         $Id$
clasohm@0:     Author: 	Lawrence C Paulson, Cambridge University Computer Laboratory
clasohm@0:     Copyright   1992  University of Cambridge
clasohm@0: 
clasohm@0: Greatest fixed points
clasohm@0: *)
clasohm@0: 
clasohm@0: Gfp = Lfp +
clasohm@0: consts gfp :: "['a set=>'a set] => 'a set"
clasohm@0: rules
clasohm@0:  (*greatest fixed point*)
clasohm@0:  gfp_def "gfp(f) == Union({u. u <= f(u)})"
clasohm@0: end