From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.io/gmane.science.mathematics.categories/6330 Path: news.gmane.org!not-for-mail From: "Eduardo J. Dubuc" Newsgroups: gmane.science.mathematics.categories Subject: Re: terminology for simplicial sets Date: Thu, 21 Oct 2010 09:18:24 -0200 Message-ID: Reply-To: "Eduardo J. Dubuc" 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 1287695772 13124 80.91.229.12 (21 Oct 2010 21:16:12 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Thu, 21 Oct 2010 21:16:12 +0000 (UTC) To: Categories list Original-X-From: majordomo@mlist.mta.ca Thu Oct 21 23:16:11 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 1P92Uc-0000NB-IO for gsmc-categories@m.gmane.org; Thu, 21 Oct 2010 23:16:10 +0200 Original-Received: from mlist.mta.ca ([138.73.1.63]:36493) by smtpx.mta.ca with esmtp (Exim 4.71) (envelope-from ) id 1P92Tx-0006ac-DB; Thu, 21 Oct 2010 18:15:29 -0300 Original-Received: from majordomo by mlist.mta.ca with local (Exim 4.71) (envelope-from ) id 1P92Tt-0002Uf-Kj for categories-list@mlist.mta.ca; Thu, 21 Oct 2010 18:15:25 -0300 Precedence: bulk Xref: news.gmane.org gmane.science.mathematics.categories:6330 Archived-At: Dear Peter (which one ?) After the recent discussions on "evil", I hope we all realized that to have a "descriptive name" is very often conflictive (and evil !!). I would say also that it is always misleading. Welcome Peter May for such a simple and brief name, "Property A" is perfect !!, why hoping for something else ?. Well, seriously, very often in mathematical practice "descriptive" names are not convenient because there is no name that adapts really to the property or concept. In that case, it is much better to use a "neutral" non descriptive name, even just a letter or a meaningles combination of 2 or 3 letters and numbers (may be related to the property, like AB5 for example). I propose the following: Call the property of being invariant under equivalence of categories property IEC, and instead of "evil" use "not IEC". Greetings to all e.j. Prof. Peter Johnstone wrote: > Dear Peter, > > Many thanks. Naturally, I'd been hoping that it might have a more > descriptive name than "Property A", but if that is what it's called ... > > The reason I got interested in it: if you consider the total category > of the discrete fibration (over the simplicial category Delta) > corresponding to a given simplicial set, the full subcategory > whose objects are the non-degenerate simplices is reflective > iff Property A holds. > > Peter > [For admin and other information see: http://www.mta.ca/~cat-dist/ ]