From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.io/gmane.science.mathematics.categories/694 Path: news.gmane.org!not-for-mail From: Peter Freyd Newsgroups: gmane.science.mathematics.categories Subject: a fantastic simplification of our subject Date: Sat, 4 Apr 1998 10:42:17 -0500 (EST) Message-ID: <199804041542.KAA08190@saul.cis.upenn.edu> NNTP-Posting-Host: main.gmane.org X-Trace: ger.gmane.org 1241017125 26952 80.91.229.2 (29 Apr 2009 14:58:45 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 29 Apr 2009 14:58:45 +0000 (UTC) To: barr@math.mcgill.ca, categories@mta.ca Original-X-From: cat-dist Sun Apr 5 17:36:23 1998 Original-Received: (from Majordom@localhost) by mailserv.mta.ca (8.8.8/8.8.8) id QAA04212 for categories-list; Sun, 5 Apr 1998 16:36:35 -0300 (ADT) X-Authentication-Warning: mailserv.mta.ca: Majordom set sender to cat-dist@mta.ca using -f Original-Sender: cat-dist@mta.ca Precedence: bulk Original-Lines: 8 Xref: news.gmane.org gmane.science.mathematics.categories:694 Archived-At: I can't make Mike's proof type-check, so let me try the following: For any set-valued functor, T, from any category, let a:O -> T be the unique transformation from the empty functor. Isn't it obviously cartesian? Has Mike shown all set-valued functors are empty? Good heavens.