From: Dana Scott <dana.scott@cs.cmu.edu>
To: categories@mta.ca
Subject: Re: Categories and functors, query
Date: Sun, 7 Sep 2008 18:25:39 -0700 [thread overview]
Message-ID: <E1KceRD-0006t5-Hr@mailserv.mta.ca> (raw)
On Sep 7, 2008, at 2:33 PM, R Brown wrote:
> There is another curiosity about the axioms for a category, namely the
> infuence of the known axioms for a groupoid (Brandt, 1926). Bill
> Cockcroft
> told me that these axioms had influenced E-M. These axioms were well
> used in
> the algebra group at Chicago. However when I asked Sammy about this
> in 1985
> he firmly said `no, and was why the notion of groupoid did not
> appear as an
> example in the E-M paper'!
>
> Perhaps it was a case of forgetting the influence?
I certainly heard Saunders mention Brandt groupoids as examples.
(Not very good examples, since all maps are invertible.) But, as
everyone knows, it is not the definition of a category that
is the key part, but seeing that functors and natural
transformations are interesting.
next reply other threads:[~2008-09-08 1:25 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-09-08 1:25 Dana Scott [this message]
-- strict thread matches above, loose matches on Subject: below --
2008-09-11 9:05 R Brown
2008-09-11 0:20 Toby Bartels
2008-09-09 22:22 jim stasheff
2008-09-09 22:05 jim stasheff
2008-09-09 10:53 Nikita Danilov
2008-09-09 0:55 tholen
2008-09-08 16:00 Walter Tholen
2008-09-08 12:50 Michael Barr
2008-09-07 21:33 R Brown
2008-09-06 10:48 Johannes Huebschmann
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