From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.io/gmane.science.mathematics.categories/4659 Path: news.gmane.org!not-for-mail From: Gaucher Philippe Newsgroups: gmane.science.mathematics.categories Subject: right adjoint by forgetting relational symbols Date: Wed, 15 Oct 2008 12:03:23 +0200 Message-ID: NNTP-Posting-Host: main.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Trace: ger.gmane.org 1241020086 14255 80.91.229.2 (29 Apr 2009 15:48:06 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 29 Apr 2009 15:48:06 +0000 (UTC) To: categories@mta.ca Original-X-From: rrosebru@mta.ca Wed Oct 15 08:47:08 2008 -0300 Return-path: Envelope-to: categories-list@mta.ca Delivery-date: Wed, 15 Oct 2008 08:47:08 -0300 Original-Received: from Majordom by mailserv.mta.ca with local (Exim 4.61) (envelope-from ) id 1Kq4kY-0005L5-Ub for categories-list@mta.ca; Wed, 15 Oct 2008 08:41:11 -0300 Original-Sender: cat-dist@mta.ca Precedence: bulk X-Keywords: X-UID: 16 Original-Lines: 12 Xref: news.gmane.org gmane.science.mathematics.categories:4659 Archived-At: Dear all, I need some references for this problem. Suppose we have a locally presentable category C axiomatized by a limits theory T, so C=Mod(T). Let us forget some relational symbols in T and all axioms containing these relational symbols. One obtains a theory T'. There is a forgetful functor Mod(T) --> Mod(T'). Does this functor have always a right adjoint ? If not, what conditions must we add ? Thanks in advance. pg.