$\operatorname{v}$-numbers of integral closure filtrations of monomial ideals

TL;DR

This paper studies the v-numbers of powers and integral closures of monomial ideals, providing new formulas, bounds, and explicit computations, and explores their relationship with Castelnuovo-Mumford regularity.

Contribution

It offers an alternative proof for v-numbers of complete intersection monomial ideals and analyzes their behavior in integral closure filtrations, revealing new bounds and relationships.

Findings

v-numbers of powers of complete intersection monomial ideals are explicitly characterized

The regularity of integral closures of powers relates linearly to v-numbers for equigenerated irreducible ideals

Constructs examples where the difference between regularity and v-number is arbitrarily large

Abstract

In this article, we investigate the $\operatorname{v}$-numbers of powers of monomial ideals and their integral closures in a polynomial ring $S$. We provide an alternative proof for determining the $\operatorname{v}$-numbers of powers of complete intersection monomial ideals. Furthermore, we analyze the $\operatorname{v}$-numbers associated to integral closure filtrations of irreducible monomial ideals and explore their relationship with the Castelnuovo-Mumford regularity of these ideals. Consequently, we obtain that for all $n\geq 1$, $\operatorname{reg}(S/\overline{I^n})=\operatorname{v}(\overline{I^n})=n\alpha(I)-1$ where $I$ is an equigenerated irreducible monomial ideal. Finally, we give an upper bound for $\operatorname{v}$-numbers associated to the integral closure filtrations of complete intersection monomial ideals and explicitly compute these $\operatorname{v}$-numbers in certain cases. As a consequence, we show that for any integer $a\geq 1$, there exists a height two equigenerated complete intersection monomial ideal $I$ such that $\operatorname{reg}(S/\overline{I^n})-\operatorname{v}(\overline{I^n})=a-1$ for all $n\geq 1$. Moreover, we establish that for complete intersection monomial ideals, the $\operatorname{v}$-numbers of powers of ideals can be arbitrarily larger than the $\operatorname{v}$-numbers of integral closures of their powers.