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From: Vaughan Pratt <pratt@cs.stanford.edu>
To: Categories <categories@mta.ca>
Subject: Re: "Historical terminology"
Date: Sun, 07 Oct 2007 17:12:36 -0700	[thread overview]
Message-ID: <E1IesQR-00047n-EG@mailserv.mta.ca> (raw)

JeanBenabou wrote:
> (i) Your "guess" about cartesian closed categories is most certainly
> correct. I knew that Eilenberg/Kelly had explicitly used this name
> in their La Jolla paper, and it is probably the first instance,
> because "closed", in this sense, was first introduced in that paper,
> as far as I know..

What most impressed my students and me two decades ago, when we were
applying the concepts of EK65 to modeling concurrency, was their attempt
to define "closed" as a self-contained notion independently of any
tensor product as its left adjoint (or so it seemed to us).  This
defeated us.  Has a clearer story of that attempt, or any related story,
emerged in the meantime?

> (iii) I agree with you on the idea that the "natural" definition of
> locally  cartesian closed category  should not  imply the existence
> of a terminal  object. If I asked the question, it is because in
> Johnstone's "Elephant" he does assume a terminal  object. Has such an
> assumption become, now, commonly accepted in the definition ?

Hopefully not.  If affine geometry has no origin, why should locally
cartesian closed categories have a global reference point?  (What would
Andy Pitts have decided there, and for that matter the orientation of
profunctors in B2.7, which seems backwards from say Borceux?)

Vaughan




             reply	other threads:[~2007-10-08  0:12 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-10-08  0:12 Vaughan Pratt [this message]
  -- strict thread matches above, loose matches on Subject: below --
2007-10-08 18:18 Vaughan Pratt
2007-10-07 21:49 Prof. Peter Johnstone
2007-10-07  7:48 JeanBenabou
2007-10-05 14:52 JeanBenabou

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