Return-Path: Delivery-Date: Received: from ted.cs.uidaho.edu (no rfc931) by swan.cl.cam.ac.uk with SMTP (PP-6.4) outside ac.uk; Fri, 19 Feb 1993 10:05:40 +0000 Received: by ted.cs.uidaho.edu (16.6/1.34) id AA29331; Fri, 19 Feb 93 01:49:07 -0800 Sender: info-hol-request@edu.uidaho.cs.ted Errors-To: info-hol-request@edu.uidaho.cs.ted Precedence: bulk Received: from swan.cl.cam.ac.uk by ted.cs.uidaho.edu (16.6/1.34) id AA29326; Fri, 19 Feb 93 01:49:00 -0800 Received: from dunlin.cl.cam.ac.uk (user lcp (rfc931)) by swan.cl.cam.ac.uk with SMTP (PP-6.4) to cl; Fri, 19 Feb 1993 09:48:35 +0000 To: info-hol@edu.uidaho.cs.ted Cc: nipkow@de.tu-muenchen.informatik Subject: Completeness proofs Date: Fri, 19 Feb 93 09:48:30 +0000 From: Lawrence C Paulson Message-Id: <"swan.cl.ca.802:19.02.93.09.48.38"@cl.cam.ac.uk> Tobias Nipkow proved the completeness of propositional logic using Isabelle's HOL. This proof is also available (in a rather different form, using fixed point theorems) in Isabelle's ZF set theory. Both proofs are included in the distribution: files HOL/ex/prop-log.ML and ZF/ex/prop-log.ML. There is no need to formalize the notion of proof. It is only necessary to formalize the set of theorems as an inductive definition. Larry Paulson