src/CCL/Gfp.thy

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