From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.io/gmane.science.mathematics.categories/7849 Path: news.gmane.org!not-for-mail From: Andrej Bauer Newsgroups: gmane.science.mathematics.categories Subject: A category internal to itself Date: Wed, 4 Sep 2013 11:23:19 +0200 Message-ID: Reply-To: Andrej Bauer NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-Trace: ger.gmane.org 1378320361 22713 80.91.229.3 (4 Sep 2013 18:46:01 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 4 Sep 2013 18:46:01 +0000 (UTC) To: categories list Original-X-From: majordomo@mlist.mta.ca Wed Sep 04 20:46:05 2013 Return-path: Envelope-to: gsmc-categories@m.gmane.org Original-Received: from smtp3.mta.ca ([138.73.1.186]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1VHI5b-00023s-SZ for gsmc-categories@m.gmane.org; Wed, 04 Sep 2013 20:46:04 +0200 Original-Received: from mlist.mta.ca ([138.73.1.63]:34796) by smtp3.mta.ca with esmtp (Exim 4.80) (envelope-from ) id 1VHI4M-000288-Ck; Wed, 04 Sep 2013 15:44:46 -0300 Original-Received: from majordomo by mlist.mta.ca with local (Exim 4.71) (envelope-from ) id 1VHI4M-0006nv-1u for categories-list@mlist.mta.ca; Wed, 04 Sep 2013 15:44:46 -0300 Precedence: bulk Xref: news.gmane.org gmane.science.mathematics.categories:7849 Archived-At: Chatting at a conference, the question came up why there is no (non-trivial) category which is "internal to itself" (interpret this in some sensible sense). And over coffee we thought this must be well known, but not to us. Can somene shed some light on the matter? With kind regards, Andrej [For admin and other information see: http://www.mta.ca/~cat-dist/ ]