PreprintCC BY-NC-SA 4.0arXiv
Structural properties of admissible subgraphs and the depth of symbolic powers of cover ideals
Abstract
Let G be a simple graph with cover ideal J(G) in a polynomial ring S = k[x1, …, xn]. For each integer t ≥ 1, let αt(G) denote the maximum size of an ordered matching M of G with alternating path length ℓ(M) ≤ 2t − 1. Hang, Tam, and Vu established that depth (S/J(G)(t)) ≤ n − 1 − αt(G) for all t ≥ 1, where J(G)(t) is the t-th symbolic power of J(G). In this paper, we introduce a natural hereditary class of graphs 𝒫k for which this inequality holds with equality for every t ≥ 1. We prove that 𝒫k contains all distance-hereditary graphs, and we show that within the class of chordal graphs, 𝒫k coincides with the class of distance-hereditary (or gem-free) graphs.
Related
- Covering powers of cycles with equivalence subgraphs
- Uniform bounds on symbolic powers in regular rings
- Symbolic Powers and Asymptotic Invariants of GL-Invariant Ideals
- Regularity of symbolic powers of complementary edge ideals
- Comparisons between ordinary and symbolic powers of edge ideals with respect to regularity and depth
BibTeX
@misc{hang2026structural,
title = {{Structural properties of admissible subgraphs and the depth of symbolic powers of cover ideals}},
author = {Nguyen Thu Hang and Nguyen Thi Thanh Tam and Thanh Vu},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.09316},
eprint = {2610.09316},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.09316},
note = {CC BY-NC-SA 4.0},
}
RIS
TY - UNPB
TI - Structural properties of admissible subgraphs and the depth of symbolic powers of cover ideals
AU - Nguyen Thu Hang
AU - Nguyen Thi Thanh Tam
AU - Thanh Vu
PY - 2026
DA - 2026/10/07
PB - arXiv
DO - 10.48550/arxiv.2610.09316
UR - https://arxiv.org/abs/2610.09316
AB - Let G be a simple graph with cover ideal J(G) in a polynomial ring S = k[x_1, …, x_n]. For each integer t ≥ 1, let α_t(G) denote the maximum size of an ordered matching M of G with alternating path length ℓ(M) ≤ 2t − 1. Hang, Tam, and Vu established that depth (S/J(G)^(t)) ≤ n − 1 − α_t(G) for all t ≥ 1, where J(G)^(t) is the t-th symbolic power of J(G). In this paper, we introduce a natural hereditary class of graphs 𝒫_k for which this inequality holds with equality for every t ≥ 1. We prove that 𝒫_k contains all distance-hereditary graphs, and we show that within the class of chordal graphs, 𝒫_k coincides with the class of distance-hereditary (or gem-free) graphs.
ER -