English

On the associated primes of generalized local cohomology modules

Commutative Algebra 2007-05-23 v1

Abstract

Let \fa\fa be an ideal of a commutative Noetherian ring RR with identity and let MM and NN be two finitely generated RR-modules. Let tt be a positive integer. It is shown that \AssR(H\fat(M,N))\Ass_R(H_{\fa}^t(M,N)) is contained in the union of the sets \AssR(\ExtRi(M,H\fati(N)))\Ass_R(\Ext_R^i(M,H_{\fa}^{t-i}(N))), where 0it0\leq i\leq t. As an immediate consequence, it follows that if either H\fai(N)H_{\fa}^i(N) is finitely generated for all i<ti<t or \SuppR(H\fai(N))\Supp_R(H_{\fa}^i(N)) is finite for all i<ti<t, then \AssR(H\fat(M,N))\Ass_R(H_{\fa}^t(M,N)) is finite. Also, we prove that if d=\pd(M)d=\pd(M) and n=dim(N)n=\dim(N) are finite, then H\fad+n(M,N)H_{\fa}^{d+n}(M,N) is Artinian. In particular, \AssR(H\fad+n(M,N))\Ass_R(H_{\fa}^{d+n}(M,N)) is a finite set consisting of maximal ideals.

Keywords

Cite

@article{arxiv.math/0510274,
  title  = {On the associated primes of generalized local cohomology modules},
  author = {Amir Mafi},
  journal= {arXiv preprint arXiv:math/0510274},
  year   = {2007}
}

Comments

7 pages, to appear in Communications in Algebra