Zero-free regions for the independence polynomial on restricted graph classes

Fuente: arXiv
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Auteurs principaux: Jerrum, Mark, Patel, Viresh
Format: Preprint
Publié: 2025
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author Jerrum, Mark
Patel, Viresh
author_facet Jerrum, Mark
Patel, Viresh
contents Generalising the Heilman-Lieb Theorem from statistical physics, Chudnovsky and Seymour [J. Combin. Theory Ser. B, 97(3):350--357] showed that the univariate independence polynomial of any claw-free graph has all of its zeros on the negative real line. In this paper, we show that for any fixed subdivded claw $H$ and any $Δ$, there is an open set $F \subseteq \mathbb{C}$ containing $[0, \infty)$ such that the independence polynomial of any $H$-free graph of maximum degree $Δ$ has all of its zeros outside of $F$. We also show that no such result can hold when $H$ is any graph other than a subdivided claw or if we drop the maximum degree condition. We also establish zero-free regions for the multivariate independence polynomial of $H$-free graphs of bounded degree when $H$ is a subdivided claw. The statements of these results are more subtle, but are again best possible in various senses.
format Preprint
id arxiv_https___arxiv_org_abs_2510_01466
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Zero-free regions for the independence polynomial on restricted graph classes
Jerrum, Mark
Patel, Viresh
Combinatorics
Mathematical Physics
05, 68, 82
G.2.1; G.2.2
Generalising the Heilman-Lieb Theorem from statistical physics, Chudnovsky and Seymour [J. Combin. Theory Ser. B, 97(3):350--357] showed that the univariate independence polynomial of any claw-free graph has all of its zeros on the negative real line. In this paper, we show that for any fixed subdivded claw $H$ and any $Δ$, there is an open set $F \subseteq \mathbb{C}$ containing $[0, \infty)$ such that the independence polynomial of any $H$-free graph of maximum degree $Δ$ has all of its zeros outside of $F$. We also show that no such result can hold when $H$ is any graph other than a subdivided claw or if we drop the maximum degree condition. We also establish zero-free regions for the multivariate independence polynomial of $H$-free graphs of bounded degree when $H$ is a subdivided claw. The statements of these results are more subtle, but are again best possible in various senses.
title Zero-free regions for the independence polynomial on restricted graph classes
topic Combinatorics
Mathematical Physics
05, 68, 82
G.2.1; G.2.2
url https://arxiv.org/abs/2510.01466