Stably free module

In mathematics, a stably free module is a module which is close to being free.

Definition
A module M over a ring R is stably free if there exists a free finitely generated module F over R such that $$ M \oplus F$$ is a free module.

Properties

 * A projective module is stably free if and only if it possesses a finite free resolution.
 * An infinitely generated module is stably free if and only if it is free.