Bourbaki

Proposition 6

Tag 066N, permanent. Cite it as [Bourbaki, Tag 066N].

Algebra, chapter III, § 10. Derivations

*Suppose that A\mathbf{A} is a unital associative graded K\mathbf{K}-algebra and E\mathbf{E} a graded (A,A)(\mathbf{A}, \mathbf{A})-bimodule. If d:A→Ed : \mathbf{A} \to \mathbf{E} is an ε\varepsilon-derivation of degree δ\delta, then, for every finite sequence (xi)1≤i≤n(x_i)_{1 \leq i \leq n} of homogeneous elements of A\mathbf{A}, of respective degrees ξi\xi_i (1≤i≤n1 \leq i \leq n),

d(x1x2…xn)=∑i=1nεδ,ξ1+⋯+ξi−1x1⋯xi−1(dxi)xi+1⋯xn. d(x_1 x_2 \ldots x_n) = \sum_{i=1}^n \varepsilon_{\delta, \xi_1 + \cdots + \xi_{i-1}} x_1 \cdots x_{i-1} (dx_i) x_{i+1} \cdots x_n.
Formula (21) is trivial for n=0n = 0 and is proved by induction on nn, taking account of (4) (no. 2).

Bourbaki puts the proof directly after the statement, so what is above is the statement and its proof together.

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Cites

Nothing.

Transcribed from the printed edition, 1998, Springer. Not translated.