Discussion of Homotopy Type Theory and Univalent Foundations
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From: Vladimir Voevodsky <vlad...@ias.edu>
To: Benedikt Ahrens <benedik...@gmail.com>
Cc: "Prof. Vladimir Voevodsky" <vlad...@ias.edu>,
	Univalent Mathematics <univalent-...@googlegroups.com>,
	homotopytypetheory <homotopyt...@googlegroups.com>
Subject: Re: [HoTT] about the HTS
Date: Thu, 23 Feb 2017 13:08:06 -0500	[thread overview]
Message-ID: <91160F61-2A67-4B1F-9A4A-F3510B99E9D3@ias.edu> (raw)
In-Reply-To: <484524d2-4054-5b7a-14af-e68a8e4b8375@gmail.com>

I could not find where he defines the univalent (intensional) equality. It seems that all his equalities are strict.


> On Feb 23, 2017, at 9:57 AM, Benedikt Ahrens <benedik...@gmail.com> wrote:
> 
> 
> 
> On 02/23/2017 03:47 PM, Vladimir Voevodsky wrote:
>> Just a thought… Can we devise a version of the HTS where exact
>> equality types are not available for the universes such that, even
>> with the exact equality, HTS would remain a univalent theory.
>> 
>> Maybe only some types should be equipped with the exact equality and
>> this should be a special quality of types.
>> 
>> Vladimir.
>> 
>> PS If there are higher inductive types then the exact equality should
>> not be available for them either.
> 
> 
> Paolo Capriotti, in his PhD thesis "Models of Type Theory with Strict
> Equality" [1], has studied strict equality in type theory.
> 
>> From page 69:
> 
> "Finally, universes in the strict fragment of our system are not assumed
> to be fibrant types, like in HTS."
> 
> You might be interested in Section 4.1.1, "Differences with HTS".
> 
> [1] https://arxiv.org/abs/1702.04912
> 
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  reply	other threads:[~2017-02-23 18:08 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-02-23 14:47 Vladimir Voevodsky
2017-02-23 14:57 ` [HoTT] " Benedikt Ahrens
2017-02-23 18:08   ` Vladimir Voevodsky [this message]
2017-02-23 18:52     ` Benedikt Ahrens
2017-02-23 21:45       ` Vladimir Voevodsky
     [not found]         ` <87k28fek09.fsf@capriotti.io>
2017-02-24 14:36           ` [UniMath] " Vladimir Voevodsky
2017-02-24 15:06             ` Paolo Capriotti
2017-02-24 15:10               ` Vladimir Voevodsky
2017-03-10 13:35             ` HIT Thierry Coquand
2017-02-24 14:36         ` [HoTT] about the HTS Paolo Capriotti
2017-02-25 19:19 ` Thierry Coquand
2017-02-27 18:50   ` [UniMath] " Vladimir Voevodsky
2017-02-27 18:53     ` Vladimir Voevodsky
2017-02-27 18:58       ` Thierry Coquand
2017-02-28  2:17         ` Vladimir Voevodsky
2017-03-01 20:23           ` Thierry Coquand
2017-03-20 15:12 ` Matt Oliveri
2017-03-22 16:49   ` [HoTT] " Thierry Coquand
2017-03-22 21:01     ` Vladimir Voevodsky
2017-03-23 11:22       ` Matt Oliveri
2017-03-23 11:33         ` Michael Shulman
2017-03-23 12:16           ` Matt Oliveri

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