Noetherian module

A module satisfying the ascending chain condition on submodules.
Noetherian module

An RR- MM is Noetherian if it satisfies the ascending chain condition (ACC) on : for every chain

N1N2N3 N_1 \subseteq N_2 \subseteq N_3 \subseteq \cdots

there exists kk such that Nk=Nk+1=N_k=N_{k+1}=\cdots. Equivalently, every submodule of MM is .

Noetherian modules are the natural finiteness context for many arguments by maximality and stabilization.

Examples:

  • Zn\mathbb Z^n is Noetherian as a Z\mathbb Z-module.
  • Any finitely generated module over a is Noetherian (in particular, any finitely generated abelian group).
  • (Nonexample) n1Z\bigoplus_{n\ge 1}\mathbb Z is not Noetherian: the submodules generated by the first kk basis vectors form a strictly increasing chain.