From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.io/gmane.science.mathematics.categories/6009 Path: news.gmane.org!not-for-mail From: Sergey Goncharov Newsgroups: gmane.science.mathematics.categories Subject: Re: Tensor of monads Date: Fri, 30 Jul 2010 03:02:28 +0200 Message-ID: References: Reply-To: Sergey Goncharov NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Trace: dough.gmane.org 1280528684 19596 80.91.229.12 (30 Jul 2010 22:24:44 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Fri, 30 Jul 2010 22:24:44 +0000 (UTC) Cc: categories@mta.ca To: "Prof. Peter Johnstone" Original-X-From: majordomo@mlist.mta.ca Sat Jul 31 00:24:42 2010 Return-path: Envelope-to: gsmc-categories@m.gmane.org Original-Received: from smtpx.mta.ca ([138.73.1.138]) by lo.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1Oey0P-0006pj-FH for gsmc-categories@m.gmane.org; Sat, 31 Jul 2010 00:24:41 +0200 Original-Received: from mlist.mta.ca ([138.73.1.63]:51708) by smtpx.mta.ca with esmtp (Exim 4.71) (envelope-from ) id 1OexyM-0002Wx-ME; Fri, 30 Jul 2010 19:22:34 -0300 Original-Received: from majordomo by mlist.mta.ca with local (Exim 4.71) (envelope-from ) id 1OexyK-0000Yh-0I for categories-list@mlist.mta.ca; Fri, 30 Jul 2010 19:22:32 -0300 In-Reply-To: Precedence: bulk Xref: news.gmane.org gmane.science.mathematics.categories:6009 Archived-At: On 07/29/2010 03:24 PM, Prof. Peter Johnstone wrote: > Sorry, the previous posting was nonsense -- a bisemilattice is the > same thing as a semilattice, by the Eckmann-Hilton argument. > However, if you leave out the zero, and consider the "set of > nonempty subsets" monad, this time on the category of sets of > cardinality 2^n - 1 for some n, you do get a counterexample. This looks fine! But I guess, Eckmann-Hilton argument does not apply to your previous example because it presupposes that the monoidal structures share the unit, which was not the case there, was it? Thanks a lot, -- Sergey Goncharov, Junior Researcher DFKI Bremen Phone: +49-421-218-64276 Safe and Secure Cognitive Systems Fax: +49-421-218-9864276 Cartesium, Enrique-Schmidt-Str. 5 Email: Sergey.Goncharov@dfki.de D-28359 Bremen Site: www.dfki.de/sks/staff/sergey ------------------------------------------------------------- Deutsches Forschungszentrum fuer Kuenstliche Intelligenz GmbH Firmensitz: Trippstadter Strasse 122, D-67663 Kaiserslautern Geschaeftsfuehrung: Prof. Dr. Dr. h.c. mult. Wolfgang Wahlster (Vorsitzender) Dr. Walter Olthoff Vorsitzender des Aufsichtsrats: Prof. Dr. h.c. Hans A. Aukes Amtsgericht Kaiserslautern, HRB 2313 ------------------------------------------------------------- [For admin and other information see: http://www.mta.ca/~cat-dist/ ]