(* Title: HOL/Lfp.thy ID: $Id$ Author: Lawrence C Paulson, Cambridge University Computer Laboratory Copyright 1992 University of Cambridge The Knaster-Tarski Theorem *) Lfp = Product_Type + constdefs lfp :: ['a set=>'a set] => 'a set "lfp(f) == Inter({u. f(u) <= u})" (*least fixed point*) end