Discussion of Homotopy Type Theory and Univalent Foundations
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From: "'Urs Schreiber' via Homotopy Type Theory" <HomotopyTypeTheory@googlegroups.com>
To: Michael Shulman <shulman@sandiego.edu>
Cc: Homotopy Type Theory <HomotopyTypeTheory@googlegroups.com>
Subject: Re: [HoTT] What is knot in HOTT?
Date: Fri, 20 Jul 2018 17:45:17 +0400	[thread overview]
Message-ID: <CA+Kbugc2hfcfc+bASYjVWSgyV8phC=rfT0rL4FAiN1gDf3RbEw@mail.gmail.com> (raw)
In-Reply-To: <CAOvivQyQtpR9jKOzwoDM=rDjx7XrJ6BKRvLZAX7On628c=hdWw@mail.gmail.com>

> Once we have the "smooth real numbers", wouldn't we just define S^1
> and S^3 in terms of them as usual?  Or are you saying that the problem
> is in characterizing the smooth reals inside differential cohesion?

Yes.

Possibly one could make progress by declaring shape to be homotopy
localization at some type A^1 of which we only demand that it be
homogeneous (as in Def. 4.8 in arxiv.org/abs/1806.05966) and then
focus attention on A^n-manifolds (as in Def. 7.1).

One could maybe declare that a smooth n-sphere to be an A^n-manifold
whose shape is equivalent to Disc(S^n). Classically, this should work
away from dimensions in which there are exotic spheres, hence in
particular for the case n <= 3 of relevance in knot theory.

Best wishes,
urs

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  reply	other threads:[~2018-07-20 13:45 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-19  5:18 José Manuel Rodriguez Caballero
2018-07-19  5:45 ` Egbert Rijke
2018-07-19  8:55   ` Ali Caglayan
2018-07-19 15:31     ` Michael Shulman
2018-07-20 10:27       ` 'Urs Schreiber' via Homotopy Type Theory
2018-07-20 13:32         ` Michael Shulman
2018-07-20 13:45           ` 'Urs Schreiber' via Homotopy Type Theory [this message]
2018-07-20 14:54             ` Michael Shulman
2018-07-20 15:17               ` Joyal, André
2018-07-20 16:40               ` 'Urs Schreiber' via Homotopy Type Theory
2018-07-20 16:42                 ` 'Urs Schreiber' via Homotopy Type Theory
2019-11-20 19:13     ` Ali Caglayan
2019-11-20 21:02       ` andré hirschowitz
2018-07-19 17:56   ` Daniel R. Grayson
2018-07-19 18:38     ` Egbert Rijke
2018-07-19 20:07       ` José Manuel Rodriguez Caballero

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