Sparse graphs with an independent or foresty minimum vertex cut

Fuente: arXiv
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Main Authors: Cheng, Kun, Tang, Yurui, Zhan, Xingzhi
Format: Preprint
Published: 2024
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author Cheng, Kun
Tang, Yurui
Zhan, Xingzhi
author_facet Cheng, Kun
Tang, Yurui
Zhan, Xingzhi
contents A connected graph is called fragile if it contains an independent vertex cut. In 2002 Chen and Yu proved that every connected graph of order $n$ and size at most $2n-4$ is fragile, and in 2013 Le and Pfender characterized the non-fragile graphs of order $n$ and size $2n-3.$ It is natural to consider minimum vertex cuts. We prove two results. (1) Every connected graph of order $n$ with $n\ge 7$ and size at most $\lfloor 3n/2\rfloor$ has an independent minimum vertex cut; (2) every connected graph of order $n$ with $n\ge 7$ and size at most $2n$ has a foresty minimum vertex cut. Both results are best possible.
format Preprint
id arxiv_https___arxiv_org_abs_2412_03869
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Sparse graphs with an independent or foresty minimum vertex cut
Cheng, Kun
Tang, Yurui
Zhan, Xingzhi
Combinatorics
05C35, 05C40, 05C69
A connected graph is called fragile if it contains an independent vertex cut. In 2002 Chen and Yu proved that every connected graph of order $n$ and size at most $2n-4$ is fragile, and in 2013 Le and Pfender characterized the non-fragile graphs of order $n$ and size $2n-3.$ It is natural to consider minimum vertex cuts. We prove two results. (1) Every connected graph of order $n$ with $n\ge 7$ and size at most $\lfloor 3n/2\rfloor$ has an independent minimum vertex cut; (2) every connected graph of order $n$ with $n\ge 7$ and size at most $2n$ has a foresty minimum vertex cut. Both results are best possible.
title Sparse graphs with an independent or foresty minimum vertex cut
topic Combinatorics
05C35, 05C40, 05C69
url https://arxiv.org/abs/2412.03869