From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.io/gmane.science.mathematics.categories/6750 Path: news.gmane.org!not-for-mail From: Messing Newsgroups: gmane.science.mathematics.categories Subject: Re: Comments on a wikipedia article on a Timeline of Category theory Date: Fri, 08 Jul 2011 18:46:11 -0400 Message-ID: References: Reply-To: Messing NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Trace: dough.gmane.org 1310171358 5685 80.91.229.12 (9 Jul 2011 00:29:18 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Sat, 9 Jul 2011 00:29:18 +0000 (UTC) Cc: Ronnie Brown , "categories@mta.ca" , George Janelidze To: "Fred E.J. Linton" Original-X-From: majordomo@mlist.mta.ca Sat Jul 09 02:29:11 2011 Return-path: Envelope-to: gsmc-categories@m.gmane.org Original-Received: from smtpx.mta.ca ([138.73.1.30]) by lo.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1QfLPy-0006Xj-OB for gsmc-categories@m.gmane.org; Sat, 09 Jul 2011 02:29:11 +0200 Original-Received: from mlist.mta.ca ([138.73.1.63]:40869) by smtpx.mta.ca with esmtp (Exim 4.71) (envelope-from ) id 1QfLOQ-00061K-9M; Fri, 08 Jul 2011 21:27:34 -0300 Original-Received: from majordomo by mlist.mta.ca with local (Exim 4.71) (envelope-from ) id 1QfLOP-00071F-I3 for categories-list@mlist.mta.ca; Fri, 08 Jul 2011 21:27:33 -0300 In-Reply-To: Precedence: bulk Xref: news.gmane.org gmane.science.mathematics.categories:6750 Archived-At: Concerning Fred Linton's comment about Wikipedia entries in general and Andre's comment about the categories timeline entry in prticular: 1) The 11th edition of the Britanica, with entries written by ad signed by Bertrand Russell and other philosophical and intellectual luminaries is justly renowned. The French analogue, the Enclyclopedie Universalis with many of the mathematical articles written by and signed by Jean Dieudonne is equally distinguished (see in particular Dieudonne's entry on analytic number theory). That Wikipedia can not compare is obvious. Nevertheless, in my view, it has its uses. While the entries on etale or crystalline cohomology were not written by Grothendieck, Artin, Deligne or Berthelot, they contain for non-experts some insights and supply references. The idiom "let the buyer beware" is apt here. 2) I agree with Andre. An imperfect timeline can be corrected and improved upon, but it is an initial effort. By definition, any timeline is a skeletal outline and, by its very nature, can never be a definitive historical text concerning whatever it concerns itself with. Let me take a specific example not mentioned in the Wikipedia timeline. In the late 1970's Goresky-Macpherson invented the theory of perverse sheaves. This theory was further developed by many others and in particular, Beilinson-Berstein-Deligne in Asterisque 100. What is "well known" to those who have looked at this text's introduction is that Gabber was to be a fourth author of this monograph, but he refused to let his name appear, because he thought that the other three authors were not sufficiently careful with regard to (technical) foundational questions. As I do not know who created the current Wikipedia timeline, I do not know if this individual knows or cares what a perverse sheaf is. Bill Messing [For admin and other information see: http://www.mta.ca/~cat-dist/ ]