From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.io/gmane.science.mathematics.categories/1487 Path: news.gmane.org!not-for-mail From: Wilkins E B Newsgroups: gmane.science.mathematics.categories Subject: Osius' set theory Date: Mon, 17 Apr 2000 14:12:50 +0100 Organization: University of Essex Message-ID: <38FB0DD2.DD7B2B@essex.ac.uk> NNTP-Posting-Host: main.gmane.org Mime-Version: 1.0 X-Trace: ger.gmane.org 1241017871 31488 80.91.229.2 (29 Apr 2009 15:11:11 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 29 Apr 2009 15:11:11 +0000 (UTC) To: Category mailing list Original-X-From: rrosebru@mta.ca Mon Apr 17 11:38:01 2000 -0300 Original-Received: (from Majordom@localhost) by mailserv.mta.ca (8.9.3/8.9.3) id LAA16485 for categories-list; Mon, 17 Apr 2000 11:30:32 -0300 (ADT) X-Authentication-Warning: mailserv.mta.ca: Majordom set sender to cat-dist@mta.ca using -f X-Mailer: Mozilla 4.6 [en] (X11; I; Linux 2.2.14 i686) X-Accept-Language: en Original-Sender: cat-dist@mta.ca Precedence: bulk Original-Lines: 17 Xref: news.gmane.org gmane.science.mathematics.categories:1487 Archived-At: Hello, In his 1974 paper Osius showed that there are enough transitive objects in the initial topos to define a naive set theory. He then goes on the assume his topoi are well-pointedness and produces a characterisation of the category of sets in terms familiar to set theorists. I'm wondering whether anyone has produced an axiomatic set theory from Osius' naive set theory which characterises the initial topos. -- Dr Elwood Wilkins e-mail: elwood@essex.ac.uk Senior Research Officer tel: (+44) (0)1206 872336 Department of Computer Science fax: (+44) (0)1206 872788 University of Essex, Colchester, Essex, UK