From: "Daniel R. Grayson" <danielrich...@gmail.com>
To: Homotopy Type Theory <HomotopyT...@googlegroups.com>
Subject: Re: Conjecture
Date: Sun, 2 Apr 2017 17:35:04 -0700 (PDT) [thread overview]
Message-ID: <3016af27-384d-4b95-9a04-5c803e08608e@googlegroups.com> (raw)
In-Reply-To: <1cd04354-59ba-40b4-47ce-9eef3ca3112f@googlemail.com>
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Here's a fact related to the current discussion, which I have formalized
today. I would appreciate knowing
whether it's already known. It gives a criterion for factoring through the
propositional truncation
when the target is of h-level 3.
Definition squash_to_HLevel_3 {X : UU} {Y : HLevel 3}
(f : X -> Y) (c : ∏ x x', f x = f x') :
(∏ x, c x x = idpath (f x)) ->
(∏ x x' x'', c x x'' = c x x' @ c x' x'') ->
∥ X ∥ -> Y.
You may find it in WellOrderedSets.v
<https://github.com/DanGrayson/UniMath/blob/well-ordering-2/UniMath/Combinatorics/WellOrderedSets.v> on
one of my branches.
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next prev parent reply other threads:[~2017-04-03 0:35 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-27 21:57 Conjecture Martin Escardo
2017-03-29 21:08 ` [HoTT] Conjecture Nicolai Kraus
2017-03-29 22:05 ` Martin Escardo
2017-03-30 10:59 ` Michael Shulman
2017-03-30 19:22 ` Egbert Rijke
2017-03-30 23:02 ` Nicolai Kraus
2017-03-30 22:49 ` Nicolai Kraus
2017-03-31 16:09 ` Martin Escardo
2017-04-05 19:37 ` Martin Escardo
2017-04-06 0:23 ` Jon Sterling
2017-04-06 5:55 ` Martin Escardo
2017-04-06 12:40 ` Vladimir Voevodsky
2017-04-06 13:50 ` Martin Escardo
[not found] ` <81c0782f-9287-4111-a4f1-01cb9c87c7e8@cs.bham.ac.uk>
2017-04-06 16:09 ` Martin Escardo
2017-04-06 11:52 ` Thomas Streicher
2017-04-07 9:49 ` Martin Escardo
2017-04-07 17:11 ` Michael Shulman
2017-04-07 18:10 ` Martin Escardo
2017-04-03 0:35 ` Daniel R. Grayson [this message]
2017-04-03 2:20 ` [HoTT] Conjecture Favonia
2017-04-03 9:56 ` Nicolai Kraus
2017-04-03 11:50 ` Daniel R. Grayson
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