Bourbaki

Proposition 9

Tag 064K, permanent. Cite it as [Bourbaki, Tag 064K].

Algebra, chapter III, § 8. Determinants

Let MM be an A\mathbf{A}-module with a basis (ei)i∈J(e_i)_{i \in J} (finite or otherwise) whose indexing set JJ is totally ordered. For every integer p>0p > 0, let (eH)H∈Sp(J)(e_H)_{H \in \mathfrak{S}_p(J)} be the corresponding basis of ∧p(M)\wedge^p(M) (§ 7, no. 8). Let (xi)1≤i≤p(x_i)_{1 \leq i \leq p} be a sequence of pp elements of MM; let

xi=∑j∈Jξjiejfor i∈I={1,p} x_i = \sum_{j \in J} \xi_{ji} e_j \quad \text{for } i \in I = \{1, p\}

and let XX denote the matrix (ξji)(\xi_{ji}) of type (J,I)(J, I). Then

x1∧x2∧⋯∧xp=∑H∈Fp(J)(det⁡XH,I)eH. x_1 \wedge x_2 \wedge \cdots \wedge x_p = \sum_{H \in \mathfrak{F}_p(J)} (\det X_{H,I}) e_H.

where HH runs through the set Fp(J)\mathfrak{F}_p(J) of subsets of JJ with pp elements.

This follows immediately from formula (12) of no. 4 and formula (6) of no. 3.

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

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Cites

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