From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.io/gmane.science.mathematics.categories/9243 Path: news.gmane.org!.POSTED!not-for-mail From: Thomas Streicher Newsgroups: gmane.science.mathematics.categories Subject: Re: Functors arising from a relational Grothendieck construction Date: Sat, 17 Jun 2017 11:27:03 +0200 Message-ID: References: Reply-To: Thomas Streicher NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: blaine.gmane.org 1497724355 15202 195.159.176.226 (17 Jun 2017 18:32:35 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Sat, 17 Jun 2017 18:32:35 +0000 (UTC) Cc: categories@mta.ca To: Luc Pellissier Original-X-From: majordomo@mlist.mta.ca Sat Jun 17 20:32:31 2017 Return-path: Envelope-to: gsmc-categories@m.gmane.org Original-Received: from smtp2.mta.ca ([198.164.44.40]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1dMIWN-0003gn-Jd for gsmc-categories@m.gmane.org; Sat, 17 Jun 2017 20:32:31 +0200 Original-Received: from mlist.mta.ca ([138.73.1.63]:34144) by smtp2.mta.ca with esmtp (Exim 4.80) (envelope-from ) id 1dMIX0-0006Sp-UO; Sat, 17 Jun 2017 15:33:10 -0300 Original-Received: from majordomo by mlist.mta.ca with local (Exim 4.71) (envelope-from ) id 1dMIVp-0006FB-L5 for categories-list@mlist.mta.ca; Sat, 17 Jun 2017 15:31:57 -0300 Content-Disposition: inline In-Reply-To: Precedence: bulk Xref: news.gmane.org gmane.science.mathematics.categories:9243 Archived-At: Dear Luc, I have noticed that, obviously, 2-valued distributors are not closed under composition in Set-valued distributors. The reason is that in the latter case the existential quantifier in composition of relations is understood in a proof relevant way. So I really don't understand what you mean by Grothendieck construction applied to a presheaf taking vaues in Rel. Thomas [For admin and other information see: http://www.mta.ca/~cat-dist/ ]