lfp.thy
author nipkow
Wed, 22 Dec 1993 12:43:37 +0100
changeset 26 5e3aa998e94e
parent 0 7949f97df77a
permissions -rw-r--r--
added Pair_eq to pair_ss in prod.ML removed it locally in llist.ML because preconditions of the form <a,b> = <?x,?y>, which used to be solved by reflexivity, now rewrote to a = ?x & b = ?y, which is not solved by reflexivity.

(*  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