Category Theory
Zulip Server
Archive

You're reading the public-facing archive of the Category Theory Zulip server.
To join the server you need an invite. Anybody can get an invite by contacting Matteo Capucci at name dot surname at gmail dot com.
For all things related to this archive refer to the same person.


Stream: community: general

Topic: The error in Kapranov–Voevodsky


view this post on Zulip David Michael Roberts (Jul 30 2020 at 08:52):

Maybe we have finally tracked it down...

https://arxiv.org/abs/2007.14505

Finally, we prove a version of the homotopy hypothesis for the infinity-groupoids in the weak model, and exhibit a specific mistake in a proof by Kapranov and Voevodsky that had previously been refuted indirectly.

Though I seem to think there was another paper not too long ago that also claimed to have found the specific mistake.

view this post on Zulip Amar Hadzihasanovic (Jul 30 2020 at 09:25):

Hi, a while ago we had a discussion about this here, in this thread :)
I've known what the error was for a while, but that discussion made me realise that there could be some interest in having it published somewhere. So I wrote it down in this paper.

view this post on Zulip Amar Hadzihasanovic (Jul 30 2020 at 09:26):

Anyway, I'll take the chance to say that I'd be happy to get comments or feedback on the paper!

view this post on Zulip Amar Hadzihasanovic (Jul 30 2020 at 09:34):

This started as a revision of an older draft but then there was a lot of new content, a lot of old content that didn't fit anymore, and I made it a new one.

The main purpose is to give a framework for “higher-dimensional rewriting”, by which I mean broadly all sorts of diagrammatic manipulations (such as “cutting and pasting” diagrams) in all dimensions, which is nearly as expressive as polygraphs/strict higher categories but avoids the pitfalls of strictness (unsoundness for homotopical algebra).
So I hope it can be useful to applied CT when it is forced to go higher than dimensions 2 or 3, with their safety net of coherence and strictification theorems.

view this post on Zulip Amar Hadzihasanovic (Jul 30 2020 at 09:41):

It's a long paper, so when I have time I'd like to write a brief “user's manual” on how to formalise diagrams in this framework. Maybe in time for the next ACT conference...