From: Michael Shulman <shulman@sandiego.edu>
To: "Andrée Ehresmann" <andree.ehresmann@u-picardie.fr>
Cc: Mike Stay <metaweta@gmail.com>, categories <categories@mta.ca>
Subject: Re: Some questions about different notions of "theory"
Date: Thu, 9 Nov 2017 16:04:42 -0800 [thread overview]
Message-ID: <E1eDIid-00007o-ND@mlist.mta.ca> (raw)
In-Reply-To: <E1eCtgt-0002ba-K3@mlist.mta.ca>
On Thu, Nov 9, 2017 at 3:26 AM, Andrée Ehresmann
<andree.ehresmann@u-picardie.fr> wrote:
> I have been
> surprised to see the definition given in nLab of a sketch as a category
> with some limit-cones and co-limit-cones. For us, a 'sketch' is a
> category S (or even a graph) with some distinguished cones and co-cones
> (but not necessarily (co-)limit-cones).
Thanks for pointing this out. I think this is an error on the nLab
page, or perhaps a sloppy phrasing that got misinterpreted by a later
editor; I'll fix it. In the case when a sketch is a graph rather than
a category, it has to come equipped also with some distinguished
diagrams that are supposed to commute in its models, right?
[For admin and other information see: http://www.mta.ca/~cat-dist/ ]
next prev parent reply other threads:[~2017-11-10 0:04 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-07 1:13 Mike Stay
2017-11-07 23:57 ` ptj
2017-11-09 7:13 ` How can we have a categorical definition " Patrik Eklund
2017-11-10 13:33 ` Steve Vickers
2017-11-09 11:26 ` Some questions about different notions " Andrée Ehresmann
2017-11-10 0:04 ` Michael Shulman [this message]
[not found] ` <Prayer.1.3.5.1711072357070.4648@carrot.maths.cam.ac.uk>
2017-11-09 16:03 ` Mike Stay
2017-11-10 0:00 ` ptj
[not found] ` <5A05AAB4.5020000@cs.bham.ac.uk>
2017-11-10 16:49 ` How can we have a categorical definition " Patrik Eklund
[not found] ` <508ad670e2ff1525f0596b3c79485c04@cs.umu.se>
2017-11-10 17:28 ` Steve Vickers
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