From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.io/gmane.science.mathematics.categories/2915 Path: news.gmane.org!not-for-mail From: Philippe Gaucher Newsgroups: gmane.science.mathematics.categories Subject: Re: Quasi-categories Date: Mon, 28 Nov 2005 08:06:08 +0100 Message-ID: <200511280806.09112.gaucher@pps.jussieu.fr> References: Reply-To: gaucher@pps.jussieu.fr NNTP-Posting-Host: main.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: quoted-printable X-Trace: ger.gmane.org 1241018981 6341 80.91.229.2 (29 Apr 2009 15:29:41 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 29 Apr 2009 15:29:41 +0000 (UTC) To: categories@mta.ca Original-X-From: rrosebru@mta.ca Mon Nov 28 12:08:06 2005 -0400 Return-path: Envelope-to: categories-list@mta.ca Delivery-date: Mon, 28 Nov 2005 12:08:06 -0400 Original-Received: from Majordom by mailserv.mta.ca with local (Exim 4.52) id 1EglTO-0001tR-Rz for categories-list@mta.ca; Mon, 28 Nov 2005 12:03:22 -0400 User-Agent: KMail/1.7.1 In-Reply-To: Content-Disposition: inline Original-Sender: cat-dist@mta.ca Precedence: bulk X-Keywords: X-UID: 60 Original-Lines: 24 Xref: news.gmane.org gmane.science.mathematics.categories:2915 Archived-At: Le samedi 26 Novembre 2005 18:42, vous avez =E9crit : > In answer to Carl Futia > > Charles Ehresmann has called such "gadgets" quasi-categories in > "Introduction to the theory of structured categories" (Kansas 1966) > reprinted in "Charles Ehresmann: Oeuvres completes et commentees" Part > III-2. > > Sincerely > Andree C. Ehresmann Dear All, One told me very recently that Joyal is writting a book about=20 "quasi-categories". But with a different meaning. A quasi-category is a=20 simplicial set satisfying a condition a little bit weaker than the Kan=20 condition. Morally speaking, two composable arrows have several possible=20 compositions, up to homotopy. I dont know whether Joyal reads this=20 mailing-list ?=20 pg.