lfp.thy
author lcp
Thu, 07 Oct 1993 10:29:23 +0100
changeset 6 4448d76f87ef
parent 0 7949f97df77a
permissions -rw-r--r--
used ~= for "not equals" and ~: for "not in"

(*  Title: 	HOL/lfp.thy
    ID:         $Id$
    Author: 	Lawrence C Paulson, Cambridge University Computer Laboratory
    Copyright   1992  University of Cambridge

The Knaster-Tarski Theorem
*)

Lfp = Sum +
consts lfp :: "['a set=>'a set] => 'a set"
rules
 (*least fixed point*)
 lfp_def "lfp(f) == Inter({u. f(u) <= u})"
end