From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.io/gmane.science.mathematics.categories/5555 Path: news.gmane.org!not-for-mail From: Dusko Pavlovic Newsgroups: gmane.science.mathematics.categories Subject: Re: Logical consequences of descent theory Date: Wed, 3 Feb 2010 12:02:25 -0800 Message-ID: References: Reply-To: Dusko Pavlovic NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 (Apple Message framework v936) Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Content-Transfer-Encoding: 7bit X-Trace: ger.gmane.org 1265295471 2525 80.91.229.12 (4 Feb 2010 14:57:51 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 4 Feb 2010 14:57:51 +0000 (UTC) To: Bas Spitters Original-X-From: categories@mta.ca Thu Feb 04 15:57:48 2010 Return-path: Envelope-to: gsmc-categories@m.gmane.org Original-Received: from mailserv.mta.ca ([138.73.1.1]) by lo.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1Nd39P-0002Jq-4Q for gsmc-categories@m.gmane.org; Thu, 04 Feb 2010 15:57:47 +0100 Original-Received: from Majordom by mailserv.mta.ca with local (Exim 4.61) (envelope-from ) id 1Nd2IL-0003GC-GY for categories-list@mta.ca; Thu, 04 Feb 2010 10:02:57 -0400 Original-Sender: categories@mta.ca Precedence: bulk Xref: news.gmane.org gmane.science.mathematics.categories:5555 Archived-At: On Feb 3, 2010, at 6:57 AM, Bas Spitters wrote: > A number of people have suggested that descent theory has been/ can be > used to obtain logical results. [snip] > Any suggestions or pointers about the logical interpretation of > descent theory would be appreciated. long long time ago there was a paper about the logical meaning of descent with the beck-chevalley condition: @inproceedings{PavlovicD:interpolation, author = "Dusko Pavlovic", title = "Categorical interpolation: descent and the Beck-Chevalley condition without direct images", booktitle = "Category Theory, Proceedings, Como 1990", editor = "A.~Carboni et al.", publisher = "Springer Verlag", series = LNM, volume = "1488", pages = "306--326", year = "1991" } more interestingly, one can also go back, and work out the exact logical conditions for descent, which are weaker than the beck- chevalley. -- dusko [For admin and other information see: http://www.mta.ca/~cat-dist/ ]