From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.io/gmane.science.mathematics.categories/6438 Path: news.gmane.org!not-for-mail From: Michael Shulman Newsgroups: gmane.science.mathematics.categories Subject: source, sinks, and ? Date: Sun, 2 Jan 2011 15:26:58 -0800 Message-ID: Reply-To: Michael Shulman NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 X-Trace: dough.gmane.org 1294013566 4275 80.91.229.12 (3 Jan 2011 00:12:46 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Mon, 3 Jan 2011 00:12:46 +0000 (UTC) To: categories Original-X-From: majordomo@mlist.mta.ca Mon Jan 03 01:12:42 2011 Return-path: Envelope-to: gsmc-categories@m.gmane.org Original-Received: from smtpx.mta.ca ([138.73.1.114]) by lo.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1PZY2U-0007zg-H1 for gsmc-categories@m.gmane.org; Mon, 03 Jan 2011 01:12:42 +0100 Original-Received: from mlist.mta.ca ([138.73.1.63]:55049) by smtpx.mta.ca with esmtp (Exim 4.71) (envelope-from ) id 1PZY2K-0001sL-U3; Sun, 02 Jan 2011 20:12:32 -0400 Original-Received: from majordomo by mlist.mta.ca with local (Exim 4.71) (envelope-from ) id 1PZY2H-0000zo-Uf for categories-list@mlist.mta.ca; Sun, 02 Jan 2011 20:12:30 -0400 Precedence: bulk Xref: news.gmane.org gmane.science.mathematics.categories:6438 Archived-At: A family of morphisms { x_i --> y }_{i \in I} in some category, all with the same codomain, is called a "sink" or a "cocone". A family { x --> y_j }_{j \in J} all with the same domain is called a "source" or a "cone". Is there a name for a family of the form { x_i --> y_j }_{i \in I, j \in J} ? A cylinder? Or a frustrum (since I \neq J)? Mike [For admin and other information see: http://www.mta.ca/~cat-dist/ ]