From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.io/gmane.science.mathematics.categories/6759 Path: news.gmane.org!not-for-mail From: Marta Bunge Newsgroups: gmane.science.mathematics.categories Subject: RE: size_question_encore Date: Sun, 10 Jul 2011 13:43:16 -0400 Message-ID: References: <4683_1310312511_4E19C83F_4683_87_1_E1Qfw7A-0008Cc-WC@mlist.mta.ca> Reply-To: Marta Bunge NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable X-Trace: dough.gmane.org 1310397980 12442 80.91.229.12 (11 Jul 2011 15:26:20 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Mon, 11 Jul 2011 15:26:20 +0000 (UTC) To: , Original-X-From: majordomo@mlist.mta.ca Mon Jul 11 17:26:15 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 1QgIND-0005j1-Lm for gsmc-categories@m.gmane.org; Mon, 11 Jul 2011 17:26:15 +0200 Original-Received: from mlist.mta.ca ([138.73.1.63]:55551) by smtpx.mta.ca with esmtp (Exim 4.71) (envelope-from ) id 1QgIL3-0005p3-IB; Mon, 11 Jul 2011 12:24:01 -0300 Original-Received: from majordomo by mlist.mta.ca with local (Exim 4.71) (envelope-from ) id 1QgIL2-0006tj-RF for categories-list@mlist.mta.ca; Mon, 11 Jul 2011 12:24:00 -0300 In-Reply-To: <4683_1310312511_4E19C83F_4683_87_1_E1Qfw7A-0008Cc-WC@mlist.mta.ca> Precedence: bulk Xref: news.gmane.org gmane.science.mathematics.categories:6759 Archived-At: Dear Andre=2C I believe that you misunderstood the comment made in Bunge-Hermida (2011) c= oncerning model structures. In particular=2C I do not know what you meant b= y your saying "I disagree with your conclusion".=A0We say precisely in Sect= ion 3 (Remark 3.6) that the two model structures mentioned - namely the Joy= al-Tierney and the Lack model structures on Cat(S)=2C S a Grothendieck topo= s=2C are different=2C and why. I think then that we agree.=A0 Best=2CMarta =A0 > From: joyal.andre@uqam.ca > To: categories@mta.ca > Subject: categories: RE: size_question_encore > Date: Sun=2C 10 Jul 2011 09:30:07 -0400 >=20 > dear Marta=2C >=20 > I apologise=2C I had forgoten our conversation! > My memory was never good=2C and it is getting worst. >=20 > You wrote: >=20 > >No=2C I am not thinking of the analogue of Steve Lack's model =20 > structure since=2C strictly speaking=2C > >it has nothing to do with stacks. Comments to that effect (with =20 > which Steve agrees) are included > >in the Bunge-Hermida paper. It was actually a surprise to discover =20 > that after trying to do what > >you suggest and failing. >=20 > I disagree with your conclusion. I looked at your paper with Hermida. > We are not talking about the same model structure. The fibrations in =20 > 2Cat(S) defined > by Steve Lack (your definition 7.1) are too weak when the topos S does =20 > not satify the axiom of choice. > Equivalently=2C his generating set of trivial cofibrations is too small. >=20 > Nobody has read my paper with Myles > groupoids=2C JPAA=2C Vol 89=2C 1993>. >=20 > Best=2C > Andr=E9 >=20 >=20 >=20 [For admin and other information see: http://www.mta.ca/~cat-dist/ ]