English

Bass numbers over local rings via stable cohomology

Commutative Algebra 2012-08-23 v1

Abstract

For any non-zero finite module M of finite projective dimension over a noetherian local ring R with maximal ideal m and residue field k, it is proved that the natural map Ext_R(k,M)-->Ext_R(k,M/mM) is non-zero when R is regular and is zero otherwise. A noteworthy aspect of the proof is the use of stable cohomology. Applications include computations of Bass series over certain local rings.

Keywords

Cite

@article{arxiv.1208.4458,
  title  = {Bass numbers over local rings via stable cohomology},
  author = {Luchezar L. Avramov and Srikanth B. Iyengar},
  journal= {arXiv preprint arXiv:1208.4458},
  year   = {2012}
}

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7 pages