Discussion of Homotopy Type Theory and Univalent Foundations
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From: Andrew Polonsky <andrew....@gmail.com>
To: Michael Shulman <shu...@sandiego.edu>
Cc: Homotopy Type Theory <HomotopyT...@googlegroups.com>
Subject: Re: [HoTT] Different notions of equality; terminology
Date: Tue, 19 Jul 2016 01:01:12 +0200	[thread overview]
Message-ID: <CABcT7WCxdHSuWdHc+5DwO98ovHx_-9bszE=kOJuuDPg5ZfyZxQ@mail.gmail.com> (raw)
In-Reply-To: <CAOvivQw15pOvi9wzWFpB2WcwmgxB=uw-826xNmxUck57VagEQA@mail.gmail.com>

>>> case I think it better to use a word that conveys *exactly* what the
>>> distinction is,
>>
>> The distinction is that it is the equality
>> predicate/formula/thing-you-can-prove-or-inhabit.
>
> "Predicate/formula/thing-you-can-prove-or-inhabit" is a long-winded
> way of saying "type".

However, that distinction was present before types.  It is indeed
illogical to call "typal" something which was there before types were
invented.

>> In type theory with reflection rule, one can think of all equalities
>> as "definitional", including those that appear in the hypothesis of
>> the reflection rule.
>
> Only if you are willing to redefine the word "definition".

I am quite happy with it as is.

Andrew

  parent reply	other threads:[~2016-07-18 23:01 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-07-18 20:45 Andrew Polonsky
2016-07-18 21:03 ` [HoTT] " Andrej Bauer
2016-07-18 21:05 ` Vladimir Voevodsky
2016-07-18 21:13   ` Andrew Polonsky
     [not found]     ` <2506A3A8-8AC0-4B49-AD1E-D660A7A15245@ias.edu>
     [not found]       ` <CABcT7WDYqUY=efCTvdRpdW98aDSXpjfHGo9pJz2jBNa3yNXCgQ@mail.gmail.com>
     [not found]         ` <085E4ACF-BD06-484F-ACA3-17DD6249CF76@ias.edu>
     [not found]           ` <CABcT7WBKxFhcvuBP66wOcUzU1uPNUqPqXoSYW4aCJv4c8U7iuQ@mail.gmail.com>
2016-07-18 21:45             ` Vladimir Voevodsky
2016-07-18 21:16   ` Dimitris Tsementzis
2016-07-18 21:17 ` Jon Sterling
2016-07-18 21:24   ` Andrew Polonsky
     [not found] ` <CAOvivQyZzdyhFFPfqkH4W+Z--78t0LEVWtthLhCpDxUkJNUrMQ@mail.gmail.com>
2016-07-18 22:20   ` Andrew Polonsky
2016-07-18 22:24     ` Jon Sterling
     [not found]     ` <CAOvivQy44FvN_bVD+nby8t0BnnTYf38dR5=s31_Yv_VsDOzLCA@mail.gmail.com>
2016-07-18 22:43       ` Andrew Polonsky
     [not found]         ` <CAOvivQw15pOvi9wzWFpB2WcwmgxB=uw-826xNmxUck57VagEQA@mail.gmail.com>
2016-07-18 23:01           ` Andrew Polonsky [this message]
2016-07-19 12:53             ` Michael Shulman
2016-07-19 16:49               ` Jon Sterling
2016-07-19 19:07                 ` Egbert Rijke
2016-07-20  2:45                 ` Dan Licata
2016-07-19 23:19 ` Martin Hotzel Escardo

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