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Projective modules over polynomial rings: a constructive approach

✍ Scribed by S. Barhoumi; H. Lombardi; I. Yengui


Publisher
John Wiley and Sons
Year
2009
Tongue
English
Weight
138 KB
Volume
282
Category
Article
ISSN
0025-584X

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✦ Synopsis


Abstract

We give a constructive proof of the fact that finitely generated projective modules over a polynomial ring with coefficients in a PrΓΌfer domain R with Krull dimension ≀ 1 are extended from R. In particular, we obtain constructively that finitely generated projective R[X~1~, …, X~n~ ]‐modules, where R is a Bezout domain with Krull dimension ≀ 1, are free. Our proof is essentially based on a dynamical method for decreasing the Krull dimension and a constructive rereading of the original proof given by Maroscia and Brewer & Costa. Moreover, we obtain a simple constructive proof of a result due to Lequain and Simis stating that finitely generated modules over R[X~1~, …, X~n~ ], n β‰₯ 2, are extended from R if and only if this holds for n = 1, where R is an arithmetical ring with finite Krull dimension (Β© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)


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