Bourbaki

Corollary 3

Tag 04L9, permanent. Cite it as [Bourbaki, Tag 04L9].

Commutative Algebra, chapter IV, § 2. Primary decomposition

Let A,A′A, A' be two rings and hh a homomorphism from AA to A′A'. Suppose that AA is semi-local and Noetherian and that A′A' is a finitely generated AA-module. Then the ring A′A' is semi-local and Noetherian; if mm is a defining ideal of AA, mA′mA' is a defining ideal of A′A'.

We know that A′A' is a Zariski ring with the mA′mA'-adic topology (Chapter III, § 3, no. 3, Proposition 7). As A/mA/m is Artinian (Corollary 2) and A′/mA′A'/mA' is a finitely generated (A/m)(A/m)-module, A′/mA′A'/mA' is an Artinian ring, hence A′A' is semi-local and mA′mA' is a defining ideal of A′A' (Corollary 2).

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

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Transcribed from the printed volume. Not translated.