Zulip Chat Archive

Stream: Is there code for X?

Topic: TensorProduct of Endomorphism rings


Edison Xie (Jan 27 2025 at 14:45):

Do we have that for a commutative ring R, Module.End R (Fin n → R) ⊗[R] Module.End R (Fin m → R) ≃ₐ[R] Module.End R ((Fin n → R) ⊗[R] (Fin m → R))? I'm asking this because I'm trying to show tensor product of azumaya algebras is still azumaya.

Edison Xie (Jan 27 2025 at 14:48):

Moreover, do we have for finitely generated projective R-modules M and N, Module.End R M ⊗[R] Module.End R N ≃ₐ[R] Module.End R (M ⊗[R] N)?

Eric Wieser (Jan 27 2025 at 15:50):

@loogle TensorProduct _ (Module.End _ _) (Module.End _ _)

loogle (Jan 27 2025 at 15:50):

:search: Module.endTensorEndAlgHom, Module.endTensorEndAlgHom_apply

Edison Xie (Jan 27 2025 at 16:16):

hmmmm yeah that's the map

Junyan Xu (Jan 29 2025 at 17:16):

For free modules there is the LinearEquiv homTensorHomEquiv, which you can combine with the AlgHom to get the AlgEquiv. I'm about to generalize it to finite projective modules.

Edison Xie (Jan 30 2025 at 01:02):

I'm doing this generation right now :((


Last updated: May 02 2025 at 03:31 UTC