Commit 2025-01-02 19:57 cc5b32e6
View on Github →feat(Algebra/Colimit): the directed system of finitely generated submodules (#20264)
We show that every module is the direct limit of its finitely generated submodules.
As a consequence of this and the fact that tensor products preserves colimits, we show that if M
and P
are arbitrary modules and N
is a finitely generated submodule of a module P
, then two elements of N ⊗ M
have the same image in P ⊗ M
if and only if they already have the same image in N' ⊗ M
for some finitely generated submodule N' ≥ N
. This is the theorem Submodule.FG.exists_rTensor_fg_inclusion_eq
.