From: David Leduc <david.leduc6@googlemail.com>
To: categories@mta.ca
Subject: Equality as an adjunction
Date: Thu, 2 Sep 2010 01:40:12 +0000 [thread overview]
Message-ID: <E1Or9Uc-00034j-JW@mlist.mta.ca> (raw)
In "Categorical Logic", Pitts explains that equality can be defined as
an adjunction. See Fig. 8, page 55
(http://www.cl.cam.ac.uk/~amp12/papers/catl/catl.ps.gz)
He writes the definition as a bidirectional typing rule for the
internal language of a suitable category.
Phi |- P(x,x) [x:A]
===================
Phi, x=x' |- P(x,x') [x x':A]
What are the left and right adjoint functors here?
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next reply other threads:[~2010-09-02 1:40 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-02 1:40 David Leduc [this message]
2010-09-02 15:22 ` Robert Seely
2010-09-02 17:56 ` Michael Shulman
2010-09-02 22:54 ` Andrej Bauer
2010-09-03 7:06 ` Vaughan Pratt
2010-09-04 4:03 ` David Leduc
[not found] ` <AANLkTikUtD3SbB+4OBRpniqgLRBg0szKYkMSwiWx+ycr@mail.gmail.com>
2010-09-04 7:21 ` David Leduc
[not found] ` <Pine.LNX.4.64.1009041105300.2080@prism.math.mcgill.ca>
2010-09-05 2:26 ` David Leduc
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