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From: Michael Barr <barr@math.mcgill.ca>
To: Categories list <categories@mta.ca>
Subject: Further to my question on adjoints
Date: Mon, 12 May 2008 08:34:18 -0400 (EDT)	[thread overview]
Message-ID: <E1JvZMk-0005yn-5A@mailserv.mta.ca> (raw)

In March I asked a question on adjoints, to which I have received no
correct response.  Rather than ask it again, I will pose what seems to be
a simpler and maybe more manageable question.  Suppose C is a complete
category and E is an object.  Form the full subcategory of C whose objects
are equalizers of two arrows between powers of E.  Is that category closed
in C under equalizers?  (Not, to be clear, the somewhat different question
whether it is internally complete.)

In that form, it seems almost impossible to believe that it is, but it is
surprisingly hard to find an example.  When E is injective, the result is
relatively easy, but when I look at examples, it has turned out to be true
for other reasons.  Probably there is someone out there who already knows
an example.

Michael




             reply	other threads:[~2008-05-12 12:34 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-05-12 12:34 Michael Barr [this message]
2008-05-12 15:43 Eduardo Dubuc
     [not found] <S4628680AbYELPnz/20080512154355Z+99@mate.dm.uba.ar>
2008-05-12 15:51 ` Michael Barr
2008-05-12 18:42 George Janelidze
2008-05-12 19:27 Michael Barr
2008-05-12 22:38 Stephen Lack
2008-05-12 23:43 George Janelidze

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