Differential graded module


In algebra,[] a differential graded module, or dg-module, is a -graded module together with a differential; i.e., a square-zero graded endomorphism of the module of degree 1 or −1, depending on the convention. In other words, it is a chain complex having a structure of a module, while a differential graded algebra is a chain complex with a structure of an algebra.
In view of the module-variant of Dold–Kan correspondence, the notion of an -graded dg-module is equivalent to that of a simplicial module; "equivalent" in the categorical sense; see #The Dold–Kan correspondence below.

The Dold–Kan correspondence

Given a commutative ring R, by definition, the category of simplicial modules are simplicial objects in the category of modules over R; denoted by sModR. Then the category can be identified with the category of differential graded modules.