From: "Vasili I. Galchin" <vigalchin@gmail.com>
To: Categories mailing list <categories@mta.ca>
Subject: P.J. Higgins' "Categories and Groupoids" question ....
Date: Wed, 19 Feb 2014 01:29:22 -0600 [thread overview]
Message-ID: <CA+0XtC-wLbGaVPL=7T49Hq+HDXWS=-7XW2oYQxSPiXSCpmaUKw@mail.gmail.com> (raw)
Hello Cat Group,
I have been reading
http://www.tac.mta.ca/tac/reprints/articles/7/tr7abs.html as well as
other works on groupoids .... I really like Higgins' book but in
Chapter 1 I keep seeing allusions to "injections" and
"surjections"instead of more general "monomorphisms" and
"epimorphisms", respectively. Is this because of his assumption (and
others ..) that starting point is a "small" graph, category, etc.,
i.e. sets not classes? If so, has anybody expanded treatment of
groupoids beyond "sets" to "classes"?
Also IMO "subgraphs" should be presented as as "monos" in the
"graph category"....
Kind regards,
Vasili
[For admin and other information see: http://www.mta.ca/~cat-dist/ ]
next reply other threads:[~2014-02-19 7:29 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-19 7:29 Vasili I. Galchin [this message]
2014-02-19 13:08 ` Steve Vickers
2014-02-20 17:46 ` Luiz Henrique
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