* HOL/record:
- provides cases/induct rules for use with corresponding Isar methods;
- "record" operation truncates to particular fixed record (acts like
a type cast);
- make_defs no longer part of default simps;
- internal definitions directly based on a light-weight abstract
theory of product types over typedef rather than datatype;
(* 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