Zulip Chat Archive
Stream: Is there code for X?
Topic: transport has_limits w.r.t. equivalence
Adam Topaz (Mar 15 2021 at 04:04):
Does mathlib know the following fact? If and are equivalent categories, and has (co)limits then has (co)limits.
Johan Commelin (Mar 15 2021 at 04:10):
This should be something like equivalence.preserves_limits
Johan Commelin (Mar 15 2021 at 04:10):
Ooh, that's not exactly it. I guess "creates limits"?
Adam Topaz (Mar 15 2021 at 04:12):
Yeah, we should have the fact that equivalences create limits.
Adam Topaz (Mar 15 2021 at 04:13):
But it seems like that's missing too. at least I can't find it.
Adam Topaz (Mar 15 2021 at 04:13):
I wanted this because I was going to make the has_limits/has_colimits instances for simplicial sets, but there were some stupid universe issues and I wanted to use the skeletal equivalence.
Scott Morrison (Mar 15 2021 at 06:10):
Eek. I'm not finding it either. @Bhavik Mehta?
Scott Morrison (Mar 15 2021 at 06:13):
(deleted)
Scott Morrison (Mar 15 2021 at 06:42):
Bhavik Mehta (Mar 15 2021 at 11:20):
docs#category_theory.adjunction.is_equivalence_creates_limits
Bhavik Mehta (Mar 15 2021 at 11:21):
It was already there
Scott Morrison (Mar 15 2021 at 11:31):
Oh, and even easier.
Scott Morrison (Mar 15 2021 at 11:31):
Scaling problems...
Bhavik Mehta (Mar 15 2021 at 11:34):
I think lots of the lemmas in that file can be hard to find, perhaps we should add something to the docstrings about them
Bhavik Mehta (Mar 15 2021 at 12:33):
Actually maybe it's sensible to move that file to limits.adjunction
and possibly split some things off into limits.equivalence
Adam Topaz (Mar 15 2021 at 14:16):
Thanks @Bhavik Mehta I'm adding a def for transporting has_(co)limits instances across an equivalence.
Last updated: Dec 20 2023 at 11:08 UTC