Bourbaki

Proposition 13

Tag 053V, permanent. Cite it as [Bourbaki, Tag 053V].

Commutative Algebra, chapter VII, § 4. Modules over integrally closed Noetherian domains

Let M be a lattice of V and u a K-automorphism of V. Then : (6)

−χ(M,u(M))=div⁡(det⁡(u)). -\chi(M, u(M)) = \operatorname{div}(\det(u)).
For all p∈Pp \in P, then ⋀n(u(M)p)=⋀n(u(Mp))\bigwedge^n (u(M)_p) = \bigwedge^n (u(M_p)); if (ei)1≤i≤n(e_i)_{1 \leq i \leq n} is a basis of MpM_p, then
⋀n(Mp)=Ap⋅e1 A e2 A…A en, \bigwedge^n (M_p) = A_p \cdot e_1 \text{ } A \text{ } e_2 \text{ } A \ldots A \text{ } e_n,

and ⋀n(u(Mp))=Ap⋅det⁡(u)e1∧e2A…Aen\bigwedge^n (u(M_p)) = A_p \cdot \det(u) e_1 \wedge e_2 \mathbf{A} \ldots \mathbf{A} e_n, whence the proposition by virtue of formula (5).

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

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Cites

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Transcribed from the printed volume. Not translated.