From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.io/gmane.science.mathematics.categories/5236 Path: news.gmane.org!not-for-mail From: Marco Grandis Newsgroups: gmane.science.mathematics.categories Subject: Re: Question on exact sequence Date: Wed, 11 Nov 2009 18:15:49 +0100 Message-ID: Reply-To: Marco Grandis NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 (Apple Message framework v752.2) Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Content-Transfer-Encoding: 7bit X-Trace: ger.gmane.org 1257994187 29643 80.91.229.12 (12 Nov 2009 02:49:47 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 12 Nov 2009 02:49:47 +0000 (UTC) To: George Janelidze , Original-X-From: categories@mta.ca Thu Nov 12 03:49:31 2009 Return-path: Envelope-to: gsmc-categories@m.gmane.org Original-Received: from mailserv.mta.ca ([138.73.1.1]) by lo.gmane.org with esmtp (Exim 4.50) id 1N8PkW-000388-3Z for gsmc-categories@m.gmane.org; Thu, 12 Nov 2009 03:49:28 +0100 Original-Received: from Majordom by mailserv.mta.ca with local (Exim 4.61) (envelope-from ) id 1N8PId-0007k5-Ru for categories-list@mta.ca; Wed, 11 Nov 2009 22:20:39 -0400 Original-Sender: categories@mta.ca Precedence: bulk Xref: news.gmane.org gmane.science.mathematics.categories:5236 Archived-At: Dear George, I have not yet received the message you are referring to. But I can reply to your question: >And do you, Marco, have a canonical connecting morphism? The morphisms I was mentioning in 'my general lemma' are canonically induced. The connecting morphism of the Snake Lemma, or of the other Lemma, are particular instances. Best wishes Marco On 11 Nov 2009, at 17:36, George Janelidze wrote: > Dear All, > > As I understand, my previous message was written after Marco's and > Steve's > messages, although I saw them only afterwards. Unfortunately I > don't have > time now, but putting these things together would be very interesting. > Specifically: > > 1. Marco vs Steve: Marco's result contains what Michael is mentioning > (=Exercise VIII.4.6 in Mac Lane's book) plus Snake Lemma, but does it > contain what Steve describes as Enrico's result? > > 2. Marco vs George: And do you, Marco, have a canonical connecting > morphism? > > 3. Steve vs George: Do you, Steve - hence Enrico - have a canonical > connecting morphism depending on what you call z : A ---> C' in > your (Steve) > message? > > George > > [For admin and other information see: http://www.mta.ca/~cat-dist/ ]