Local cohomology properties of direct summands
Commutative Algebra
2012-07-10 v2
Abstract
In this article, we prove that if is a homomorphism of Noetherian rings that splits, then for every and ideal , is finite when is finite. In addition, if is a Cohen-Macaulay ring that is finitely generated as an -module, such that all the Bass numbers of , as an -module, are finite, then all the Bass numbers of , as an -module, are finite. Moreover, we show these results for a larger class a functors introduced by Lyubeznik. As a consequence, we exhibit a Gorenstein -regular UFD of positive characteristic that is not a direct summand, not even a pure subring, of any regular ring.
Cite
@article{arxiv.1108.4455,
title = {Local cohomology properties of direct summands},
author = {Luis Nunez-Betancourt},
journal= {arXiv preprint arXiv:1108.4455},
year = {2012}
}
Comments
8 pages. References updated. Minor changes