Bourbaki

Corollary 4

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

Commutative Algebra, chapter IV, § 2. Primary decomposition

Let AA be a complete semi-local Noetherian ring, mm a defining ideal of AA, EE a finitely generated AA-module and (Fn)(F_n) a decreasing sequence of submodules of EE such that ⋂nFn=0\bigcap_n F_n = 0. Then, for all p>0p > 0, there exists n>0n > 0 such that Fn⊂mpEF_n \subset m^p E.

As AA is a Zariski ring, EE is Hausdorff and the FnF_n are closed under the mm-adic topology. On the other hand, EE is complete (Chapter III, § 2, no. 12, Corollary 1 to Proposition 16). Finally, E/mpEE/m^p E is a finitely generated module over the ring A/mpA/m^p, which is Artinian (Corollary 2); then E/mpEE/m^p E is an Artinian (A/mp)(A/m^p)-module and hence an Artinian AA-module. The corollary then follows from Chapter III, § 2, no. 7, Proposition 8.

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.