author | clasohm |
Thu, 16 Sep 1993 12:20:38 +0200 | |
changeset 0 | a5a9c433f639 |
child 124 | 858ab9a9b047 |
permissions | -rw-r--r-- |
(* Title: ZF/fixedpt.thy ID: $Id$ Author: Lawrence C Paulson, Cambridge University Computer Laboratory Copyright 1992 University of Cambridge Least and greatest fixed points *) Fixedpt = ZF + consts bnd_mono :: "[i,i=>i]=>o" lfp, gfp :: "[i,i=>i]=>i" rules (*monotone operator from Pow(D) to itself*) bnd_mono_def "bnd_mono(D,h) == h(D)<=D & (ALL W X. W<=X --> X<=D --> h(W) <= h(X))" lfp_def "lfp(D,h) == Inter({X: Pow(D). h(X) <= X})" gfp_def "gfp(D,h) == Union({X: Pow(D). X <= h(X)})" end