Zulip Chat Archive

Stream: Is there code for X?

Topic: Finiteness of tensor product


Antoine Labelle (Apr 25 2022 at 19:26):

Do we have the fact that if M and N are finite R modules, so is M ⊗ N?

Eric Wieser (Apr 25 2022 at 20:34):

docs#finite_dimensional_tensor_product

Eric Wieser (Apr 25 2022 at 20:35):

Probably the existing proof can be generalized to commutative rings

Antoine Labelle (Apr 25 2022 at 22:20):

Yes I'd want that for arbitrary commutative rings

Antoine Labelle (Apr 25 2022 at 22:21):

The proof doesn't immediatly generalize since in general we don't have bases, but it shouldn't be too hard.

Riccardo Brasca (Apr 26 2022 at 06:52):

I would prove that a module is finite iff it is the image of a surjective hom from a finite and free module (this shuld be very easy, but I think it is missing), and then use the universal property of tensor product of the two free modules to produce the surjection you need.

Junyan Xu (Apr 26 2022 at 06:54):

#13705


Last updated: Dec 20 2023 at 11:08 UTC