From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (from weis@localhost) by pauillac.inria.fr (8.6.10/8.6.6) id NAA06145 for caml-redistribution; Fri, 23 Feb 1996 13:20:09 +0100 Received: from concorde.inria.fr (concorde.inria.fr [192.93.2.39]) by pauillac.inria.fr (8.6.10/8.6.6) with ESMTP id PAA28696 for ; Thu, 22 Feb 1996 15:15:30 +0100 Received: from imag.imag.fr (imag.imag.fr [129.88.30.1]) by concorde.inria.fr (8.7.1/8.7.1) with ESMTP id PAA02417 for ; Thu, 22 Feb 1996 15:15:30 +0100 (MET) Received: from thot.imag.fr (thot.imag.fr [129.88.38.1]) by imag.imag.fr (8.6.11/8.6.9) with ESMTP id PAA14481 for ; Thu, 22 Feb 1996 15:15:28 +0100 Received: from [129.88.38.40] (pythagore.imag.fr [129.88.38.40]) by thot.imag.fr (8.6.11/8.6.9) with SMTP id PAA17621 for ; Thu, 22 Feb 1996 15:15:26 +0100 X-Sender: levy@thot.imag.fr Message-Id: Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Date: Thu, 22 Feb 1996 15:16:50 +0100 To: caml-list@pauillac.inria.fr From: Michel.Levy@imag.fr (Michel Levy) Subject: definition recursive de valeur Sender: weis D=E9finissons les deux valeurs infinies suivantes : let rec x =3D 1::x;; let rec y =3D 1::y;; x =3D y;; Demandons =E0 v=E9rifier leur =E9galit=E9s : camllight essaie de comparer x= et y par une m=E9thode qui ne se termine pas. Pour les arbres infinis rationnels (cf Prolog) l'=E9galit=E9 est d=E9cidable= : ne serait-il pas possible soit de refuser de comparer x et y, soit d'utiliser l'algorithme testant l'=E9galit=E9 de ce type d'arbre. Let us define the following infinite values : let rec x =3D 1::x ;; let rec y =3D 1::y;; x =3D y;; The evaluation of the last expression doesn't terminate. We could consider that the equations above have solutions wich are infinite rational trees and there exists a algorithm to test the equality of such trees, could it be possible either to use such an algorithm, either to refuse to test the equality. Michel Levy L.S.R. BP53x - 38041 Grenoble cedex - France Tel : 76827246 e.mail : Michel.Levy@imag.fr