Proposition 6
Tag 0633, permanent. Cite it as [Bourbaki, Tag 0633].
Algebra, chapter III, § 7. Exterior algebras
If M is a finitely generated A-module, is a finitely generated A-module; also, if M admits a generating system with n elements, then for .
Let be a generating system of M. Every element of is a linear combination of elements of the form
where the indices belong to ; by Proposition 5, these indices can be assumed to be distinct (otherwise the corresponding element is zero). If , there is no such sequence of indices and hence . If , these sequences are finite in number, which completes the proof.
Bourbaki puts the proof directly after the statement, so what is above is the statement and its proof together.