English

Remarks on the Hilbert depth of squarefree monomial ideals

Commutative Algebra 2024-04-29 v5

Abstract

Let KK be a infinite field, S=K[x1,,xn]S=K[x_1,\ldots,x_n] and 0IJS0\subset I\subsetneq J\subset S two squarefree monomial ideals. In a previous paper we proved a new formula for the Hilbert depth of J/IJ/I. In this paper, we illustrate how one can use the Stanley-Reisner correspondence between (relative) simplicial complexes and (quotients of) squarefree monomial ideals, in order to reobtain some basic properties of the Hilbert depth. More precisely, we show that depth(J/I)hdepth(J/I)dim(J/I)\operatorname{depth}(J/I)\leq \operatorname{hdepth}(J/I)\leq \dim(J/I). Also, we show that hdepth(I)hdepth(S/I)+1\operatorname{hdepth}(I)\geq \operatorname{hdepth}(S/I)+1, if S/IS/I is Cohen-Macaulay.

Keywords

Cite

@article{arxiv.2310.12339,
  title  = {Remarks on the Hilbert depth of squarefree monomial ideals},
  author = {Silviu Balanescu and Mircea Cimpoeas},
  journal= {arXiv preprint arXiv:2310.12339},
  year   = {2024}
}

Comments

10 pages; major changes (we realized that our results hold only in the squarefree case and we modified accordingly); one coauthor added