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From: Emily Riehl <eriehl@math.harvard.edu>
To: Categories <categories@mta.ca>
Subject: subgroupoids of V-categories
Date: Tue, 19 Nov 2013 13:51:41 -0500 (EST)	[thread overview]
Message-ID: <E1Vir4i-0005Cv-JA@mlist.mta.ca> (raw)

Hi all,

For general V (closed symmetric monoidal, bicomplete), is there a general
way to construct the maximal subgroupoid of a V-category C?

I think I know how to *detect* the maximal subgroupoid. A map in C is an
isomorphism iff it is representably so: Writing 1 for the monoidal unit,
we say f : 1 -> C(x,y) is an iso iff the induced map f_* : C(z,x) ->
C(z,y) is an iso in V for all z. So we might say that a V-category G with
the same objects and C and an identity-on-objects local monomorphism G ->
C is the maximal subgroupoid provided that a morphism f factors through
G(x,y) -> C(x,y) just when f is an isomorphism.

In examples, this is probably good enough, but I still would feel better
if I had a general construction of the maximal subgroupoid. I feel like
this should be some sort of weighted limit, perhaps with some additional
structure on V?

Thanks,
Emily


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             reply	other threads:[~2013-11-19 18:51 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-11-19 18:51 Emily Riehl [this message]
2013-11-19 21:24 ` Zhen Lin Low
2013-11-20 11:18 ` Ronnie Brown
2013-11-20 15:53 ` Jeff Egger

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