From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.io/gmane.science.mathematics.categories/6078 Path: news.gmane.org!not-for-mail From: Michael Barr Newsgroups: gmane.science.mathematics.categories Subject: Another question on Grothendieck Date: Mon, 30 Aug 2010 10:18:30 -0400 (EDT) Message-ID: Reply-To: Michael Barr NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-Trace: dough.gmane.org 1283185737 16606 80.91.229.12 (30 Aug 2010 16:28:57 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Mon, 30 Aug 2010 16:28:57 +0000 (UTC) To: Categories list Original-X-From: majordomo@mlist.mta.ca Mon Aug 30 18:28:56 2010 Return-path: Envelope-to: gsmc-categories@m.gmane.org Original-Received: from smtpx.mta.ca ([138.73.1.138]) by lo.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1Oq7E6-0007Uo-IL for gsmc-categories@m.gmane.org; Mon, 30 Aug 2010 18:28:54 +0200 Original-Received: from mlist.mta.ca ([138.73.1.63]:33691) by smtpx.mta.ca with esmtp (Exim 4.71) (envelope-from ) id 1Oq7DK-00073K-4Q; Mon, 30 Aug 2010 13:28:06 -0300 Original-Received: from majordomo by mlist.mta.ca with local (Exim 4.71) (envelope-from ) id 1Oq7DH-0001gU-Pk for categories-list@mlist.mta.ca; Mon, 30 Aug 2010 13:28:03 -0300 Precedence: bulk Xref: news.gmane.org gmane.science.mathematics.categories:6078 Archived-At: Grothendieck introduces, on the top of p. 209 of the Tohoku paper, the notation U_{i_0..i_p} without explanation and uses it again over the next couple pages. Here {U_i} is an open cover of a space X and I have reason to believe that this stands for the intersection of U_{i_j}. Can anyone confirm this? Or give an alternate explanation? The context is that of a claim that (when A is a sheaf) and "every U_{i_0..i_p} is A-acyclic, then"... and that awfully like the definition of a simple cover. Michael [For admin and other information see: http://www.mta.ca/~cat-dist/ ]