* right-derived functors
@ 2004-04-16 12:09 Peter Freyd
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From: Peter Freyd @ 2004-04-16 12:09 UTC (permalink / raw)
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Bill asks:
Does every geometric morphism have right-derived functors on abelian
objects?
In principle, this would not require enough injectives since the
universal property requested does not involve any specific kind of
resolution.
I think not. In my new Foreword to Abelian Categories on TAC
(www.tac.mta.ca/tac/reprints/articles/3/foreword.pdf), specifically in
the comments about pages 131-132, I recall the description of a locally
small topos in which Ext(A,B) wants to have proper classes as values.
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