From: Michael Barr <barr@math.mcgill.ca>
To: Categories list <categories@mta.ca>
Subject: A question on adjoints
Date: Tue, 18 Mar 2008 13:11:44 -0500 (EST) [thread overview]
Message-ID: <E1Jbjo3-0007W5-BJ@mailserv.mta.ca> (raw)
I guess I am getting old and dumb. This question should have been a snap
for me years ago. It is old fashioned, only a 1-categorical question and
not about internal vs. external.
Suppose F: A --> B is left adjoint to U: B --> A. Suppose a is an object
of A and b, b' objects of B such that there is an equalizer
a ---> Ub ===> Ub'. (The two arrows Ub to UB' are not assumed to be U
of arrows from B.) Does it follow that a ---> UFa ===> UFUFa is an
equalizer? The arrows are \eta a, UF\eta a and \eta UFa of course.
Michael
next reply other threads:[~2008-03-18 18:11 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-03-18 18:11 Michael Barr [this message]
2008-03-19 5:43 Vaughan Pratt
2008-03-19 18:43 Michael Barr
2008-03-19 23:41 Vaughan Pratt
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