Corollary 3
Tag 04L9, permanent. Cite it as [Bourbaki, Tag 04L9].
Commutative Algebra, chapter IV, § 2. Primary decomposition
Let be two rings and a homomorphism from to . Suppose that is semi-local and Noetherian and that is a finitely generated -module. Then the ring is semi-local and Noetherian; if is a defining ideal of , is a defining ideal of .
We know that is a Zariski ring with the -adic topology (Chapter III, § 3, no. 3, Proposition 7). As is Artinian (Corollary 2) and is a finitely generated -module, is an Artinian ring, hence is semi-local and is a defining ideal of (Corollary 2).
Bourbaki puts the proof directly after the statement, so what is above is the statement and its proof together.