src/HOLCF/Pcpo.thy
author oheimb
Tue, 10 Mar 1998 18:33:13 +0100
changeset 4721 c8a8482a8124
parent 3842 b55686a7b22c
child 5438 c89ee3a46a74
permissions -rw-r--r--
renamed is_chain to chain, is_tord to tord, replaced chain_finite by chfin

(*  Title:      HOLCF/Pcpo.thy
    ID:         $Id$
    Author:     Franz Regensburger
    Copyright   1993 Technische Universitaet Muenchen

introduction of the classes cpo and pcpo 
*)
Pcpo = Porder +

(* The class cpo of chain complete partial orders *)
(* ********************************************** *)
axclass cpo < po
        (* class axiom: *)
  cpo   "chain S ==> ? x. range(S) <<| (x::'a::po)" 

(* The class pcpo of pointed cpos *)
(* ****************************** *)
axclass pcpo < cpo

  least         "? x.!y. x<<y"

consts
  UU            :: "'a::pcpo"        

syntax (symbols)
  UU            :: "'a::pcpo"                           ("\\<bottom>")

defs
  UU_def        "UU == @x.!y. x<<y"       

(* further useful classes for HOLCF domains *)

axclass chfin<cpo

chfin 	"!Y. chain Y-->(? n. max_in_chain n Y)"

axclass flat<pcpo

ax_flat	 	"! x y. x << y --> (x = UU) | (x=y)"

end