Tight upper bounds on the hop domination number of triangle-free graphs

Fuente: arXiv
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Autori principali: Fujita, Shinya, Park, Boram
Natura: Preprint
Pubblicazione: 2025
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author Fujita, Shinya
Park, Boram
author_facet Fujita, Shinya
Park, Boram
contents For a graph $G$, a subset $S$ of $V(G)$ is a {\it hop dominating set} of $G$ if every vertex not in $S$ has a $2$-step neighbor in $S$. The {\it hop domination number}, $γ_h(G)$, of $G$ is the minimum cardinality of a hop dominating set of $G$. In this paper, we show that for a connected triangle-free graph $G$ with $n\ge 15$ vertices, if $δ(G)\ge 2$, then $γ_h(G)\le \frac{2n}{5}$, and the bound is tight. We also give some tight upper bounds on $γ_h(G)$ for {triangle-free} graphs $G$ that contain a Hamiltonian path or a Hamiltonian cycle.
format Preprint
id arxiv_https___arxiv_org_abs_2503_04124
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Tight upper bounds on the hop domination number of triangle-free graphs
Fujita, Shinya
Park, Boram
Combinatorics
For a graph $G$, a subset $S$ of $V(G)$ is a {\it hop dominating set} of $G$ if every vertex not in $S$ has a $2$-step neighbor in $S$. The {\it hop domination number}, $γ_h(G)$, of $G$ is the minimum cardinality of a hop dominating set of $G$. In this paper, we show that for a connected triangle-free graph $G$ with $n\ge 15$ vertices, if $δ(G)\ge 2$, then $γ_h(G)\le \frac{2n}{5}$, and the bound is tight. We also give some tight upper bounds on $γ_h(G)$ for {triangle-free} graphs $G$ that contain a Hamiltonian path or a Hamiltonian cycle.
title Tight upper bounds on the hop domination number of triangle-free graphs
topic Combinatorics
url https://arxiv.org/abs/2503.04124