中文

Bound on the a-invariant and reduction numbers of ideals

交换代数 2007-05-23 v1

摘要

Let RR be a dd-dimensional standard graded ring over an Artin local ring. Let MM be the unique maximal homogeneous ideal of R.R. Let hi(R)nh^i(R)_n denote the length of HMi(R)nH^i_M(R)_n, i.e. the nth graded component of the ith local cohomology module of R with respect to M. Define the Eisenbud-Goto invariant of RR to be the number EG(R)=q=0d1(d1q)hq(R)1q.EG(R)= \sum_{q=0}^{d-1} \binom{d-1}{q} h^q(R)_{1-q}. We prove that the aa-invariant of RR satisfies a(R)e(R)length(R1)+(d1)(length(R0)1)+EG(R). a(R) \leq e(R)-length(R_1)+(d-1)(length(R_0)-1)+ EG(R). Using this bound we get upper bounds for the reduction number of an mm-primary ideal of a Cohen-Macaulay local ring (R,m)(R,m) whose associated graded ring G(m)G(m) has almost maximal depth.

引用

@article{arxiv.math/0404066,
  title  = {Bound on the a-invariant and reduction numbers of ideals},
  author = {Clare D'Cruz and Vijay Kodiyalam and Jugal. K. Verma},
  journal= {arXiv preprint arXiv:math/0404066},
  year   = {2007}
}

备注

8 pages. to appear in Journal of algebra 274(2004) 594-601