Put in minimal simpset to avoid excessive simplification,
just as in revision 1.9 of HOL/indrule.ML
(* Title: HOLCF/ex/Fix2.ML
ID: $Id$
Author: Franz Regensburger
Copyright 1995 Technische Universitaet Muenchen
*)
open Fix2;
val lemma1 = prove_goal Fix2.thy "fix = gix"
(fn prems =>
[
(rtac ext_cfun 1),
(rtac antisym_less 1),
(rtac fix_least 1),
(rtac gix1_def 1),
(rtac gix2_def 1),
(rtac (fix_eq RS sym) 1)
]);
val lemma2 = prove_goal Fix2.thy "gix`F=lub(range(%i. iterate i F UU))"
(fn prems =>
[
(rtac (lemma1 RS subst) 1),
(rtac fix_def2 1)
]);