replaced option_map_SomeD by option_map_eq_Some (RS iffD1)
added option_map_eq_Some to simpset(), option_map_eq_Some RS iffD1 to claset()
(* Title: HOL/lfp.thy
ID: $Id$
Author: Lawrence C Paulson, Cambridge University Computer Laboratory
Copyright 1992 University of Cambridge
The Knaster-Tarski Theorem
*)
Lfp = Set +
consts lfp :: "['a set=>'a set] => 'a set"
rules
(*least fixed point*)
lfp_def "lfp(f) == Inter({u. f(u) <= u})"
end