Definition:Differential Complex

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Definition

Let $R$ be a commutative ring with unity.

Let $\displaystyle M = \bigoplus_{n \in \Z} M^n$ be a $\Z$-graded $R$-module that is also a differential module with differential $d$.


Then $M$ is a differential complex if the differential $d$ satisfies:

$ d \left({M^n}\right) \subseteq M^{n+1}$

for all $n \in \Z$.


The notation $d_n := d \restriction_{M_n}$ is often seen.


Also see