From: John Baez <baez@math.ucr.edu>
To: categories <categories@mta.ca>
Subject: Martins-Porter paper
Date: Mon, 28 Aug 2006 18:01:21 -0700 [thread overview]
Message-ID: <E1GIXYv-0001Nq-J4@mailserv.mta.ca> (raw)
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Interesting letter from Grothendieck!
Ronnie Brown writes:
>A recent arXiv paper by Jo=E3o Faria Martins and Tim Porter
>math.QA/0608484
>Title: On Yetter's Invariant and an Extension of the Dijkgraaf-Witten
>Invariant to Categorical Groups
>
> seems also relevant to the theme of the Baez-Shulman notes.
Yes; we didn't get into TQFTs at all in our notes, but Martins
and Porter use the classifying space of a discrete 2-group
(=3D categorical group =3D crossed module =3D gr-category) in their
construction, and that's quite relevant.
I wrote a little introduction to the Martins-Porter paper and its
antecedents at the n-category cafe:
http://golem.ph.utexas.edu/category/2006/08/categorifying_the_dijkgraafwit.=
html
Best,
jb
next reply other threads:[~2006-08-29 1:01 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-08-29 1:01 John Baez [this message]
2006-08-31 6:02 John Baez
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