English

$v$-numbers of symbolic power filtrations

Commutative Algebra 2024-12-03 v6

Abstract

We study the asymptotic behaviour of vv-number and local vv-numbers of Noetherian generalized symbolic power filtrations I={In}\mathcal I=\{I_n\} in a Noetherian N\mathbb N-graded domain and show that they are quasi-linear type. We provide sufficient conditions for the existence of the limits limnv(In)n\lim\limits_{n\to\infty}\frac{v(I_n)}{n} and limnvp(In)n\lim\limits_{n\to\infty}\frac{v_\mathfrak p(I_n)}{n} for all pA(I)\mathfrak p\in\overline A(\mathcal I). We explicitly compute local vv-numbers and vv-numbers of symbolic powers of cover ideals of complete bipartite graphs, complete graphs, cycles, KmsK_m^s and compare them with their Castelnuovo-Mumford regularity. We give an example of a bipartite graph H\mathcal H that is not a complete bipartite graph and v(J(H))>bight(I(H))1v(J(\mathcal H))>bight(I(\mathcal H))-1. This answers a question in [25, Question 3.12]. We show that for both connected bipartite graphs and connected non-bipartite graphs, the difference between the regularity and the vv-number of the cover ideals can be arbitrarily large. This strengthens and gives an alternative proof of[25,Theorem 3.10]. We provide a counterexample to a conjecture [12, Conjecture 5.4] due to A. Ficarra and E. Sgroi.

Keywords

Cite

@article{arxiv.2403.09175,
  title  = {$v$-numbers of symbolic power filtrations},
  author = {Vanmathi A and Parangama Sarkar},
  journal= {arXiv preprint arXiv:2403.09175},
  year   = {2024}
}

Comments

Major revision, new results were added in Section 3 and Section 4, and the title was changed