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On the Criteria of D.D. Anderson for Invertible and Flat Ideals

Published online by Cambridge University Press:  20 November 2018

David E. Dobbs*
Affiliation:
Department of Mathematics, University of TennesseeKnoxville, Tennessee 37996, U.S.A.
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Abstract

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Let R be an integral domain. It is proved that if a nonzero ideal I of R can be generated by n < ∞ elements, then I is invertible (i.e., flat) if and only if I(∩ Rai) =Iai for all { a1, . . ., a n﹜ ⊂ I. The article's main focus is on torsion-free R-modules E which are LCM-stable in the sense that E(RaRb) = EaEb for all a, b ∈ R. By means of linear relations, LCM-stableness is shown to be equivalent to a weak aspect of flatness. Consequently, if each finitely generated ideal of R may be 2-generated, then each LCM-stable R-module is flat. Finally, LCM-stableness of maximal ideals serves to characterize Prüfer domains, Dedekind domains, principal ideal domains, and Bézout domains amongst suitably larger classes of integral domains.

Type
Research Article
Copyright
Copyright © Canadian Mathematical Society 1986

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