From: Tom Leinster <tl@maths.gla.ac.uk>
To: categories <categories@mta.ca>
Subject: Re: weak double categories?
Date: Thu, 27 Oct 2005 22:55:51 +0100 [thread overview]
Message-ID: <1130450151.13458.19.camel@tl-linux.maths.gla.ac.uk> (raw)
In-Reply-To: <E1EVEI7-0001JV-6G@mailserv.mta.ca>
On Wed, 2005-10-26 at 13:08 -0700, John Baez wrote:
> If you weaken the notion of 2-category you get the notion of
> bicategory. Has anyone tried to correspondingly weaken the
> notion of double category, so that a bicategory is a special
> sort of "weak double category" in analogy to the ways in which
> a 2-category is a special sort of double category?
At least three parties have done this:
- Bob Pare and collaborators
- at least one Australian of the Sean Carmody/Dominic Verity/Steve Lack
generation (calling them something like "double bicategories")
- me (section 5.2 of book).
There's the question of whether you weaken in just one direction or in
both. I believe that parties 1 and 3 weaken in just one direction. But
you write
> in analogy to the ways [*plural!*] in which a 2-category is a special
> sort of double category
so I guess you're after weakening in both directions.
Tom
next prev parent reply other threads:[~2005-10-27 21:55 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-10-26 20:08 John Baez
2005-10-27 21:55 ` Tom Leinster [this message]
2005-10-28 9:10 ` Richard Garner
2005-10-28 11:32 ` Marco Grandis
2005-10-28 0:13 Ross Street
2005-10-28 21:07 John Baez
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