Simple quotients of modules #
A nonzero module with a coatomic submodule lattice has a simple quotient. In particular this applies to nonzero Noetherian modules. The categorical statement provides an epimorphism to a simple object, so it can be transported along equivalences of module and representation categories.
theorem
ModuleCat.exists_epi_simple
{R : Type u_1}
[Ring R]
(M : ModuleCat R)
[IsCoatomic (Submodule R ↑M)]
(hM : ¬CategoryTheory.Limits.IsZero M)
:
∃ (S : ModuleCat R), CategoryTheory.Simple S ∧ ∃ (f : M ⟶ S), CategoryTheory.Epi f
A nonzero module whose submodule lattice is coatomic admits an epimorphism to a simple module.