For several classes of commutative rings R it is known that every finitely generated projective R-modules is isomorphic to a direct sum of a free w x R-module and an invertible ideal of R. For instance, Steinitz 27 essenw x tially proved this for Dedekind domains. Serre 25 proved the same result for
SCr Modules over Local Rings
β Scribed by Jee Heub Koh
- Publisher
- Elsevier Science
- Year
- 2001
- Tongue
- English
- Weight
- 134 KB
- Volume
- 239
- Category
- Article
- ISSN
- 0021-8693
No coin nor oath required. For personal study only.
β¦ Synopsis
We show that the following two conditions, for each integer r G 1, are equivalent for a finitely generated module M over a complete Noetherian local ring Ε½ . R, α :
embeddable in E r , where E denotes the injective hull of the residue field Rrα. Ε½ . r Ε½ . b Either M ; E , or else dim Hom Rrα, M s kr and there is no R r α R Ε½ . ry kq1 prime ideal α such that dim Rrα s 1 and Rrα is embeddable in M.
Ε½ This is an extension of a result of M. Hochster 1977, Trans. Amer. Math. Soc. 231, . 463α488 , which is the case r s 1. We show other results related to these conditions.
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