When does LCM-stability ensure flatness at primes of depth one? (Q1093686)
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scientific article; zbMATH DE number 4023437
| Language | Label | Description | Also known as |
|---|---|---|---|
| English | When does LCM-stability ensure flatness at primes of depth one? |
scientific article; zbMATH DE number 4023437 |
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When does LCM-stability ensure flatness at primes of depth one? (English)
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1986
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Let R be a noetherian integral domain, K its field of quotients, and \(\bar R\) its integral closure in K. Let M be a torsion-free finite R- module. We say M is LCM-stable if \((aR\cap bR)M=aM\cap bM\) holds for any a,b\(\in R\). Main results: Theorem. Suppose \(\bar R\) is finite over R and M is LCM-stable. Then M is reflexive if and only if \(M_ P\) is flat over \(R_ P\) for every prime ideal P with depth(R\({}_ P)=1.\) Theorem. Assume that \(\bar R\) is finite over R and let A be a finite, locally simple extension ring of R. If A is reflexive and LCM-stable over R, then A is flat over R.
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LCM-stability
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flatness
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reflexive module
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noetherian integral domain
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depth
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