English

On some local cohomology modules

Commutative Algebra 2007-05-23 v1 Algebraic Geometry

Abstract

Let R be a commutative Noetherian d-dimensional complete equicharacterisitc regular local ring and let I be an ideal of R such that every minimal prime over I has height at most c. Let v=d - [(d-2)/c]-1 and v'=d - [(d-1)/c]. It has been known that the i-th local cohomology module of any R-module M with support in I vanishes for i>v', and if I is prime, for i>v; both results are sharp. The purpose of this paper is to prove a necessary and sufficient condition, for a not necessarily prime I, for the vanishing in the range i>v, i.e. in the same range as for a prime ideal. The condition is in terms of some combinatorial properties of the set of the minimal primes of I whose sum is zero-dimensional. A version for non-regular local rings is also proven.

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Cite

@article{arxiv.math/0609508,
  title  = {On some local cohomology modules},
  author = {Gennady Lyubeznik},
  journal= {arXiv preprint arXiv:math/0609508},
  year   = {2007}
}

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24 pages