From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.io/gmane.science.mathematics.categories/6415 Path: news.gmane.org!not-for-mail From: Neil Ghani Newsgroups: gmane.science.mathematics.categories Subject: Sigma and Products Date: Fri, 10 Dec 2010 09:45:27 +0000 Message-ID: Reply-To: Neil Ghani NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 (Apple Message framework v1081) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable X-Trace: dough.gmane.org 1291984347 27502 80.91.229.12 (10 Dec 2010 12:32:27 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Fri, 10 Dec 2010 12:32:27 +0000 (UTC) To: categories@mta.ca Original-X-From: majordomo@mlist.mta.ca Fri Dec 10 13:32:24 2010 Return-path: Envelope-to: gsmc-categories@m.gmane.org Original-Received: from smtpx.mta.ca ([138.73.1.114]) by lo.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1PR299-000711-KE for gsmc-categories@m.gmane.org; Fri, 10 Dec 2010 13:32:23 +0100 Original-Received: from mlist.mta.ca ([138.73.1.63]:46496) by smtpx.mta.ca with esmtp (Exim 4.71) (envelope-from ) id 1PR28w-0006cY-Nv; Fri, 10 Dec 2010 08:32:10 -0400 Original-Received: from majordomo by mlist.mta.ca with local (Exim 4.71) (envelope-from ) id 1PR28s-0006AO-HH for categories-list@mlist.mta.ca; Fri, 10 Dec 2010 08:32:07 -0400 Precedence: bulk Xref: news.gmane.org gmane.science.mathematics.categories:6415 Archived-At: Hi=20 Sorry ... nothing deep or fundamental here. Here is a simple question which someone may know the answer to.=20 Lets say we have a fibration p:E -> B with left adjoints Sigma_f for = every reindexing functor f^*. Lets say further that E has products and = p preserves them. Are there simple conditions under which we have Sigma_{f \times g} (P \times Q)=20 iso (Sigma_f P) \times (Sigma_g Q) All the best Neil= [For admin and other information see: http://www.mta.ca/~cat-dist/ ]