Finitely presented modules over semihereditary rings

被引:2
|
作者
Couchot, Francois [1 ]
机构
[1] Univ Caen, Dept Math & Mech, Lab Nicolas Oresmc, F-14032 Caen, France
关键词
finitely presented module; local-global ring; semihereditary ring; stacked bases property; UCS-property;
D O I
10.1080/00927870701353134
中图分类号
O1 [数学];
学科分类号
0701 ; 070101 ;
摘要
We prove that each almost local-global semihereditary ring R has the stacked bases property and is almost Bezout. More precisely, if M is a finitely presented module, its torsion part tM is a direct sum of cyclic modules where the family of annihilators is an ascending chain of invertible ideals. These ideals are invariants of M. Moreover, M/tM is a projective module which is isomorphic to a direct sum of finitely generated ideals. These ideals allow us to define a finitely generated ideal whose isomorphism class is an invariant of M. The idempotents and the positive integers defined by the rank of M/tM are invariants of M too. It follows that each semihereditary ring of Krull-dimension one or of finite character, in particular each hereditary ring, has the stacked base property. These results were already proved for Prufer domains by Brewer, Katz, Klinger, Levy, and Ullery. It is also shown that every semihereditary Bezout ring of countable character is an elementary divisor ring.
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页码:2685 / 2692
页数:8
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