Zulip Chat Archive
Stream: Is there code for X?
Topic: Connecting the two different `sheafify`
Heather Macbeth (Oct 04 2023 at 22:04):
There are definitions docs#CategoryTheory.GrothendieckTopology.sheafify and docs#TopCat.Presheaf.sheafify, and I assume (?) they are supposed to give the same thing (mathematically, if not definitionally) in the case of a sheaf of types on a topological space. But it seems not to be done -- is that right?
Junyan Xu (Oct 05 2023 at 14:17):
It's a to-do item to build the forget-sheafification adjunction in the TopCat setting. Once that's done, it should be easy from
docs#CategoryTheory.sheafificationAdjunction and docs#CategoryTheory.Adjunction.leftAdjointUniq
(docs#TopCat.Sheaf.forget is defeq to docs#CategoryTheory.sheafToPresheaf)
Heather Macbeth (Oct 05 2023 at 14:22):
Thanks! I would be very happy to see that to-do item done ...
If I understand correctly, this plan would show that the two sheafify
operations are naturally isomorphic. I suppose they're not defeq?
Adam Topaz (Oct 05 2023 at 14:27):
They won't be defeq.
Last updated: Dec 20 2023 at 11:08 UTC