From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.io/gmane.science.mathematics.categories/7291 Path: news.gmane.org!not-for-mail From: Donovan Van Osdol Newsgroups: gmane.science.mathematics.categories Subject: Re: Derived cotriples Date: Tue, 22 May 2012 18:35:25 -0400 Message-ID: References: Reply-To: Donovan Van Osdol NNTP-Posting-Host: plane.gmane.org X-Trace: dough.gmane.org 1337827643 23415 80.91.229.3 (24 May 2012 02:47:23 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Thu, 24 May 2012 02:47:23 +0000 (UTC) Cc: categories@mta.ca To: Michael Barr Original-X-From: majordomo@mlist.mta.ca Thu May 24 04:47:22 2012 Return-path: Envelope-to: gsmc-categories@m.gmane.org Original-Received: from smtpx.mta.ca ([138.73.1.80]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1SXO5A-0002dV-Vs for gsmc-categories@m.gmane.org; Thu, 24 May 2012 04:47:21 +0200 Original-Received: from mlist.mta.ca ([138.73.1.63]:43691) by smtpx.mta.ca with esmtp (Exim 4.77) (envelope-from ) id 1SXO4K-00081c-Pj; Wed, 23 May 2012 23:46:28 -0300 Original-Received: from majordomo by mlist.mta.ca with local (Exim 4.71) (envelope-from ) id 1SXO4J-0008Ju-2A for categories-list@mlist.mta.ca; Wed, 23 May 2012 23:46:27 -0300 Precedence: bulk Xref: news.gmane.org gmane.science.mathematics.categories:7291 Archived-At: In my 1969 Ph.D. thesis I showed that, given a "good category for sheaf theory" and a topological space, the associated sheaf functor arises as the dual of your construction. Basically, I needed the "goodness" hypothesis so that the equalizer itself would construct the associated sheaf and thus I would not need to iterate your construction. The triple used, in this case, was the original Godement standard construction. Details can be found in Springer Lecture Notes in Mathematics, volume 236. Don [For admin and other information see: http://www.mta.ca/~cat-dist/ ]