Commit 2025-07-16 13:02 e1097802
View on Github →feat(RingTheory/TensorProduct/FG) : direct limit properties of tensor products wrt finitely generated submodules (#26717)
This PR uses the fact that a module is the directed limit of its finitely generated submodules
to establish various existence properties of finitely generated submodules wrt tensor products.
For any element u : M ⊗[R] N, there exists a finitely generated submodule P of M and an element t : P ⊗[R] N
whose image in M ⊗[R] N is equal to u.
For t : P ⊗[R] N and t' : P' ⊗[R] N as above, there exists a finitely generated submodule Q of M containing P ⊔ P'
such that the images of t and t' in Q ⊗[R] N coincide.
Similar results for base change, where M is replaced by an R-algebra A, and P, P', Q by finitely generated subalgebras of A.