From: Ross Street <ross.street@mq.edu.au>
To: Joseph Collins <joseph.collins@strath.ac.uk>
Cc: "categories@mta.ca list" <categories@mta.ca>
Subject: Re: Formally adding morphisms
Date: Sat, 16 Nov 2019 01:44:47 +0000 [thread overview]
Message-ID: <E1iW7iN-00037h-3X@rr.mta.ca> (raw)
In-Reply-To: <E1iVGVj-0003Zl-Ob@rr.mta.ca>
Dear Joseph
In 2-categorical terminology, your A_f is the coinserter of the two functors X, Y : 1 --> A.
Ross
On 13 Nov 2019, at 5:04 AM, Joseph Collins <joseph.collins@strath.ac.uk<mailto:joseph.collins@strath.ac.uk>> wrote:
Suppose that we have a category A. If we want to formally add a single morphism, say f:X -> Y, where X,Y are in A, but f is not in A, we can do the following: we look at the discrete category containing only X and Y - let us denote that as (X Y) - and the category with two objects and only a single morphism between them. Let's call this one (X -> Y).
[For admin and other information see: http://www.mta.ca/~cat-dist/ ]
next prev parent reply other threads:[~2019-11-16 1:44 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-12 18:04 Joseph Collins
2019-11-16 1:44 ` Ross Street [this message]
2019-11-17 4:58 ` Fernando Lucatelli Nunes
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