Return-Path: Delivery-Date: Received: from leopard.cs.byu.edu (no rfc931) by swan.cl.cam.ac.uk with SMTP (PP-6.5) outside ac.uk; Tue, 5 Apr 1994 11:19:03 +0100 Received: by leopard.cs.byu.edu (1.37.109.8/16.2) id AA24777; Tue, 5 Apr 1994 04:04:39 -0600 Sender: info-hol-request@lal.cs.byu.edu Errors-To: info-hol-request@lal.cs.byu.edu Precedence: bulk Received: from dworshak.cs.uidaho.edu by leopard.cs.byu.edu with SMTP (1.37.109.8/16.2) id AA24773; Tue, 5 Apr 1994 04:04:31 -0600 Received: from oberon.inmos.co.uk by dworshak.cs.uidaho.edu with SMTP (1.37.109.8/16.2) id AA13919; Tue, 5 Apr 1994 03:05:16 -0700 Received: from frogland.inmos.co.uk by oberon.inmos.co.uk; Tue, 5 Apr 1994 11:05:10 +0100 From: David Shepherd Message-Id: <3824.9404051003@frogland.inmos.co.uk> Subject: recursives defs over sets. To: info-hol@cs.uidaho.edu (info-hol mailing list) Date: Tue, 5 Apr 1994 11:03:58 +0100 (BST) X-Mailer: ELM [version 2.4 PL20] Content-Type: text Content-Length: 536 Immediate correction to my last definition which was > Actually ... a simpler version is: > > AND f g S = (?x.~(x IN (S UNION FN)) /\ R (f x) (g x)) to AND f g S = (!x.(x IN S) ==> (R (f x) (g x))) /\ (?x.~(x IN FN) /\ R (f x) (g x)) -------------------------------------------------------------------------- david shepherd: des@inmos.co.uk tel: 0454-616616 x 625 inmos ltd, 1000 aztec west, almondsbury, bristol, bs12 4sq "I am not a nut --- I am a human being."