From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.io/gmane.science.mathematics.categories/2306 Path: news.gmane.org!not-for-mail From: Galchin Vasili Newsgroups: gmane.science.mathematics.categories Subject: Semantic tableaux and intuitionistic logic Date: Fri, 30 May 2003 13:14:01 -0700 (PDT) Message-ID: <20030530201401.40220.qmail@web12203.mail.yahoo.com> NNTP-Posting-Host: main.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: ger.gmane.org 1241018563 3466 80.91.229.2 (29 Apr 2009 15:22:43 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 29 Apr 2009 15:22:43 +0000 (UTC) To: categories@mta.ca Original-X-From: rrosebru@mta.ca Fri May 30 23:18:07 2003 -0300 Return-path: Envelope-to: categories-list@mta.ca Delivery-date: Fri, 30 May 2003 23:18:07 -0300 Original-Received: from Majordom by mailserv.mta.ca with local (Exim 4.10) id 19Lvu9-0002Np-00 for categories-list@mta.ca; Fri, 30 May 2003 23:15:33 -0300 Original-Sender: cat-dist@mta.ca Precedence: bulk X-Keywords: X-UID: 56 Original-Lines: 16 Xref: news.gmane.org gmane.science.mathematics.categories:2306 Archived-At: Hello, I am only familiar with semantic tableaux for classical propositional logic (and classical 1st order logic). It seems that as an inference system it is based squarely around the law of the excluded middle because it is essentially reductio ad absurdum. Hence, as an inference system it can't be simply modified for intuitionistic propositional calculus?? (Of course, I am bringing this because the role that Heyting algebras play in Topos theory). Regards, Bill Halchin