From: David Leduc <david.leduc6@googlemail.com>
To: Robert Seely <rags@math.mcgill.ca>
Cc: categories <categories@mta.ca>
Subject: Re: Equality as an adjunction
Date: Sun, 5 Sep 2010 02:26:38 +0000 [thread overview]
Message-ID: <E1OsHNA-0005RH-T4@mlist.mta.ca> (raw)
In-Reply-To: <Pine.LNX.4.64.1009041105300.2080@prism.math.mcgill.ca>
Do you mean that I am *all* wrong when I spell out the adjunction?
Anyway, I will definitely read Lawvere's papers on the topic and maybe
your thesis although I am a bit scared by this fibrational setting.
On Sat, Sep 4, 2010 at 3:09 PM, Robert Seely <rags@math.mcgill.ca> wrote:
> I *really* suggest you look at Lawvere's papers (and I also suggest
> you might find my elaboration of these ideas helpful). What is going
> on here is essentially adjunctions (for sum and product, or
> equivalently existential and universal quantification) to
> substitution. This sort of setup occurs in a fibrational setting, and
> the functors involved are between fibres; the underlying common story
> is more compelling than just one example can suggest, I think.
>
> - all the best, Robert
>
> On Sat, 4 Sep 2010, David Leduc wrote:
>
>> Sorry, I guess my mistake is that I've got the adjunction in the wrong
>> direction: it is a left Kan extension:
>>
>> [CxC,2](Lan_Delta P, Q) =~ [C,2](P, Q o Delta)
>>
>> And equality is given by Lan_Delta T : CxC -> 2.
>> Does it always exist?
>>
>> And what was the right Kan extension in my previous mail when it exists?
>>
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prev parent reply other threads:[~2010-09-05 2:26 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-02 1:40 David Leduc
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 [this message]
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