Definition 10.5.1. Let R be a ring. Let M be an R-module.
We say M is a finite R-module, or a finitely generated R-module if there exist n \in \mathbf{N} and x_1, \ldots , x_ n \in M such that every element of M is an R-linear combination of the x_ i. Equivalently, this means there exists a surjection R^{\oplus n} \to M for some n \in \mathbf{N}.
We say M is a finitely presented R-module or an R-module of finite presentation if there exist integers n, m \in \mathbf{N} and an exact sequence
R^{\oplus m} \longrightarrow R^{\oplus n} \longrightarrow M \longrightarrow 0
Comments (0)
There are also: