Tuned function thm_proof.
(*  Title:      HOLCF/Fun3.thy
    ID:         $Id$
    Author:     Franz Regensburger
    Copyright   1993 Technische Universitaet Muenchen
Class instance of  => (fun) for class pcpo
*)
Fun3 = Fun2 +
(* default class is still term *)
instance fun  :: (term,cpo)cpo         (cpo_fun)
instance fun  :: (term,pcpo)pcpo       (least_fun)
end