From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.io/gmane.science.mathematics.categories/6966 Path: news.gmane.org!not-for-mail From: Michael J Healy Newsgroups: gmane.science.mathematics.categories Subject: Re: diagrams in computer algebra Date: Wed, 12 Oct 2011 15:47:21 -0600 Message-ID: References: Reply-To: Michael J Healy NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 (Apple Message framework v1084) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable X-Trace: dough.gmane.org 1318516250 9304 80.91.229.12 (13 Oct 2011 14:30:50 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Thu, 13 Oct 2011 14:30:50 +0000 (UTC) Cc: categories@mta.ca, soloviev@irit.fr To: Vasili I. Galchin Original-X-From: majordomo@mlist.mta.ca Thu Oct 13 16:30:46 2011 Return-path: Envelope-to: gsmc-categories@m.gmane.org Original-Received: from smtpx.mta.ca ([138.73.1.4]) by lo.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1REMJ1-0002KY-NO for gsmc-categories@m.gmane.org; Thu, 13 Oct 2011 16:30:43 +0200 Original-Received: from mlist.mta.ca ([138.73.1.63]:38076) by smtpx.mta.ca with esmtp (Exim 4.76) (envelope-from ) id 1REMHb-0002TZ-RO; Thu, 13 Oct 2011 11:29:15 -0300 Original-Received: from majordomo by mlist.mta.ca with local (Exim 4.71) (envelope-from ) id 1REMHa-000278-7W for categories-list@mlist.mta.ca; Thu, 13 Oct 2011 11:29:14 -0300 In-Reply-To: Precedence: bulk Xref: news.gmane.org gmane.science.mathematics.categories:6966 Archived-At: Vasili, Yes, I mean small. All but FinSet (an appropriate version of it, = anyway---certain functors into which are models, i.e.data respositories) = are generated from finite graphs, through categorical completion = elaborated with specified commutative diagrams, pullbacks, etc. Regards, Mike On Oct 8, 2011, at 3:55 PM, Vasili I. Galchin wrote: > Hi Mike, >=20 > Do you really mean small category or do you mean finite category? > If small category(potentially(<<< no pun intended) infinite), then I > guess using Haskell is the right choice do to its lazy evaluation > feature. >=20 > Regards, >=20 > Vasili >=20 >=20 > On Mon, Oct 3, 2011 at 1:02 PM, Michael J Healy = wrote: >> Sergei, >>=20 >> My colleagues and I have been looking for something like this for a = project. We need to be able to specify small categories as the = completions of finite graphs we are given, extend these by specifying = commutative diagrams, pullbacks, etc, of interest, then define functors = generated from graph homomorphisms, and take colimits of diagrams in = Cat, etc etc. We haven't found anything that does all this. So, we're = programming it in Haskell---one of our grad students knows the language. = We'll be happy to share our experience and will probably make the code = available. It's a work in progress. >>=20 >> Best regards, >> Mike Healy >>=20 [For admin and other information see: http://www.mta.ca/~cat-dist/ ]