Suppose that A is a unital associative graded algebra and E a graded (A,A)-bimodule. Let d:A→E be an ε-derivation of degree δ and a a homogeneous element of Zε of degree α. Then the mapping x↦a(dx) is an ε-derivation of degree δ+α.
We write d′(x)=a(dx); for x homogeneous of degree ξ in A and y∈A, by virtue of (23) and (1) (no. 1),