Finding dense minors using average degree

Fuente: arXiv
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Main Authors: Hendrey, Kevin, Norin, Sergey, Steiner, Raphael, Turcotte, Jérémie
Format: Preprint
Published: 2023
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author Hendrey, Kevin
Norin, Sergey
Steiner, Raphael
Turcotte, Jérémie
author_facet Hendrey, Kevin
Norin, Sergey
Steiner, Raphael
Turcotte, Jérémie
contents Motivated by Hadwiger's conjecture, we study the problem of finding the densest possible $t$-vertex minor in graphs of average degree at least $t-1$. We show that if $G$ has average degree at least $t-1$, it contains a minor on $t$ vertices with at least $(\sqrt{2}-1-o(1))\binom{t}{2}$ edges. We show that this cannot be improved beyond $\left(\frac{3}{4}+o(1)\right)\binom{t}{2}$. Finally, for $t\leq 6$ we exactly determine the number of edges we are guaranteed to find in the densest $t$-vertex minor in graphs of average degree at least $t-1$.
format Preprint
id arxiv_https___arxiv_org_abs_2307_01184
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Finding dense minors using average degree
Hendrey, Kevin
Norin, Sergey
Steiner, Raphael
Turcotte, Jérémie
Combinatorics
05C07, 05C35, 05C83
Motivated by Hadwiger's conjecture, we study the problem of finding the densest possible $t$-vertex minor in graphs of average degree at least $t-1$. We show that if $G$ has average degree at least $t-1$, it contains a minor on $t$ vertices with at least $(\sqrt{2}-1-o(1))\binom{t}{2}$ edges. We show that this cannot be improved beyond $\left(\frac{3}{4}+o(1)\right)\binom{t}{2}$. Finally, for $t\leq 6$ we exactly determine the number of edges we are guaranteed to find in the densest $t$-vertex minor in graphs of average degree at least $t-1$.
title Finding dense minors using average degree
topic Combinatorics
05C07, 05C35, 05C83
url https://arxiv.org/abs/2307.01184