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Bibliographic Details
Main Author: Pach, Janos
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2604.27639
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author Pach, Janos
author_facet Pach, Janos
contents Let $k\ge 2$ be fixed integer, $0<c<1$ a constant. Consider a graph $G$ with $n$ vertices and average degree $cn$. We answer a question of Simon Griffiths by showing that $G$ has $k$ vertices such that their neighborhoods together cover at least $\min(1-(1-c)^{k},\sqrt{c})n$ vertices. This result is essentially tight.
format Preprint
id arxiv_https___arxiv_org_abs_2604_27639
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle How large part of a graph can be covered by the neighborhoods of k vertices?
Pach, Janos
Combinatorics
05C35, 05C69
Let $k\ge 2$ be fixed integer, $0<c<1$ a constant. Consider a graph $G$ with $n$ vertices and average degree $cn$. We answer a question of Simon Griffiths by showing that $G$ has $k$ vertices such that their neighborhoods together cover at least $\min(1-(1-c)^{k},\sqrt{c})n$ vertices. This result is essentially tight.
title How large part of a graph can be covered by the neighborhoods of k vertices?
topic Combinatorics
05C35, 05C69
url https://arxiv.org/abs/2604.27639