Discussion of Homotopy Type Theory and Univalent Foundations
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From: Paolo Capriotti <p.capriotti@gmail.com>
To: Homotopy Type Theory <HomotopyTypeTheory@googlegroups.com>
Subject: [HoTT] Re: Precategories, Categories and Univalent categories
Date: Wed, 7 Nov 2018 02:31:51 -0800 (PST)	[thread overview]
Message-ID: <eae326a2-d223-46f9-a3e1-d5c17dd5bd8b@googlegroups.com> (raw)
In-Reply-To: <b9927646-c5f1-40b5-a070-258eb984249b@googlegroups.com>


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On Wed, 7 Nov 2018, at 10:03 AM, Ali Caglayan wrote:
> Now because we have Rezk completion every precategory is yearning to 
become
> a category, so some might argue that a distinction isn't necessery.

I wouldn't say that. Yes, there is an adjunction between categories and 
precategories, but it's not an equivalence even in an ∞-categorical sense. 
In fact, following Ayala and Francis, you can think of a precategory as a 
category C equipped with the extra structure of a type X, and a surjective 
(i.e. -1-connected) morphism X → obj C.

> What are your thoughts and opinions on this?

Whatever notion ends up being called *category*, I would say it ought to at 
least be mapped to something that is (Quillen) equivalent to the usual 
notion of category through the simplicial set interpretation. That suggests 
categories should be univalent by default.

Best,
Paolo

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  reply	other threads:[~2018-11-07 10:31 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-07 10:03 [HoTT] " Ali Caglayan
2018-11-07 10:31 ` Paolo Capriotti [this message]
2018-11-07 10:35 ` [HoTT] " Ulrik Buchholtz
2018-11-07 10:37   ` Ulrik Buchholtz
2018-11-07 11:09   ` Peter LeFanu Lumsdaine
2018-11-07 11:43     ` Ulrik Buchholtz
2018-11-07 11:50       ` Erik Palmgren
2018-11-07 11:51       ` Ulrik Buchholtz
2018-11-07 12:03         ` Erik Palmgren
2018-11-07 12:21           ` Martín Hötzel Escardó
2018-11-07 13:00             ` Erik Palmgren
2018-11-07 13:02             ` Bas Spitters
2018-11-07 13:47               ` Ali Caglayan
2018-11-07 13:53               ` Thomas Streicher
2018-11-07 14:05                 ` Thorsten Altenkirch
2018-11-07 13:58       ` Thorsten Altenkirch
2018-11-07 14:14         ` Ulrik Buchholtz
2018-11-07 14:27           ` Peter LeFanu Lumsdaine
     [not found]             ` <CAOvivQyG1q9=3YoS8hX3bRQK0yi+mpBnJu+rqb3oon0uPLpZ4A@mail.gmail.com>
2018-11-07 20:01               ` Michael Shulman
2018-11-08 21:37               ` Martín Hötzel Escardó
2018-11-08 21:43                 ` Michael Shulman
2018-11-09  4:43                   ` Andrew Polonsky
2018-11-09 10:18                     ` Ulrik Buchholtz
2018-11-09 10:57                       ` Paolo Capriotti
2018-11-07 14:31           ` Thorsten Altenkirch
2018-11-07 14:05       ` Peter LeFanu Lumsdaine
2018-11-07 14:28         ` Ulrik Buchholtz
2018-11-07 15:35           ` Thomas Streicher
2018-11-07 16:54             ` Thorsten Altenkirch
2018-11-07 16:56               ` Thorsten Altenkirch
2018-11-07 17:31                 ` Eric Finster
2018-11-08 11:58               ` Thomas Streicher
2018-11-08 12:23                 ` [HoTT] " Emily Riehl
2018-11-08 12:28                   ` Emily Riehl
2018-11-08 14:01                     ` Thomas Streicher
2018-11-08 16:10                   ` Thomas Streicher
2018-11-08 14:38                 ` [HoTT] " Michael Shulman
2018-11-08 21:08                   ` Thomas Streicher
2018-11-08 21:30                     ` Michael Shulman
2018-11-09 11:56                       ` Thomas Streicher
2018-11-09 13:46                         ` Michael Shulman
2018-11-09 15:06                           ` Thomas Streicher
2018-11-08 16:01                 ` Thorsten Altenkirch
2018-11-08 19:39                   ` Thorsten Altenkirch
2018-11-07 20:00         ` Michael Shulman
2018-11-08 21:35 ` Martín Hötzel Escardó

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