From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.io/gmane.science.mathematics.categories/3983 Path: news.gmane.org!not-for-mail From: Eduardo Dubuc Newsgroups: gmane.science.mathematics.categories Subject: Re: locally cartesian closed categories Date: Tue, 9 Oct 2007 11:18:18 -0300 (ART) Message-ID: NNTP-Posting-Host: main.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Trace: ger.gmane.org 1241019642 11186 80.91.229.2 (29 Apr 2009 15:40:42 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 29 Apr 2009 15:40:42 +0000 (UTC) To: categories@mta.ca Original-X-From: rrosebru@mta.ca Tue Oct 9 22:00:10 2007 -0300 Return-path: Envelope-to: categories-list@mta.ca Delivery-date: Tue, 09 Oct 2007 22:00:10 -0300 Original-Received: from Majordom by mailserv.mta.ca with local (Exim 4.61) (envelope-from ) id 1IfPpA-0001FN-1c for categories-list@mta.ca; Tue, 09 Oct 2007 21:53:20 -0300 Original-Sender: cat-dist@mta.ca Precedence: bulk X-Keywords: X-UID: 40 Original-Lines: 28 Xref: news.gmane.org gmane.science.mathematics.categories:3983 Archived-At: hi, yet another point in favor that terminal object and products should not be mandatory in locally cartesian closed categories: terminal (or products) implies connection, fiber products don't. compare with the notion of cofilter category (axiom similar to existence of products), is connected, while pseudofiltered (axiom similar to existence of fiber products), is not connected. this is essentially the difference between filterness and cofilterness, with all what it means same thing, fiber products and not products are in the essence of the notion of locally cartesian closedness ps: congratulations to Bob R., I fully agree with all the good things that were said recently about his handling of this list (not an easy job !). eduardo dubuc