Localization respects associated primes for Noetherian rings: Difference between revisions

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Latest revision as of 16:26, 12 May 2008

This article defines a result where the base ring (or one or more of the rings involved) is Noetherian
View more results involving Noetherianness or Read a survey article on applying Noetherianness

Statement

Suppose A is a Noetherian commutative unital ring and M is any A-module (not necessarily finitely generated. Let S be a multiplicatively closed subset of A.

There is a natural inclusion on spectra:

Spec(S−1A)→Spec(A)

The set of associated primes for S−1M as an S−1A-module is the inverse image in Spec(S−1A) of the set of associated primes for M as an A-module.

If we identify Spec(S−1A) with its image, a subset of Spec(A), then we can write:

AssS−1AS−1M=AssAM∩Spec(S−1A)

Proof

The key ingredient in the proof is the fact that if m∈M, the union of annihilators of all elements of Sm, can be realized as the annihilator of a single element sm.