Hamilton transversals in tournaments

Fuente: arXiv
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Main Authors: Chakraborti, Debsoumya, Kim, Jaehoon, Lee, Hyunwoo, Seo, Jaehyeon
Format: Preprint
Published: 2023
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author Chakraborti, Debsoumya
Kim, Jaehoon
Lee, Hyunwoo
Seo, Jaehyeon
author_facet Chakraborti, Debsoumya
Kim, Jaehoon
Lee, Hyunwoo
Seo, Jaehyeon
contents It is well-known that every tournament contains a Hamilton path, and every strongly connected tournament contains a Hamilton cycle. This paper establishes transversal generalizations of these classical results. For a collection $\mathbf{T}=\{T_1,\dots,T_m\}$ of not-necessarily distinct tournaments on a common vertex set $V$, an $m$-edge directed graph $\mathcal{D}$ with vertices in $V$ is called a $\mathbf{T}$-transversal if there exists a bijection $ϕ\colon E(\mathcal{D})\to [m]$ such that $e\in E(T_{ϕ(e)})$ for all $e\in E(\mathcal{D})$. We prove that for sufficiently large $m$ with $m=|V|-1$, there exists a $\mathbf{T}$-transversal Hamilton path. Moreover, if $m=|V|$ and at least $m-1$ of the tournaments $T_1,\ldots,T_m$ are assumed to be strongly connected, then there is a $\mathbf{T}$-transversal Hamilton cycle. In our proof, we utilize a novel way of partitioning tournaments which we dub $\mathbf{H}$-partition.
format Preprint
id arxiv_https___arxiv_org_abs_2307_00912
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Hamilton transversals in tournaments
Chakraborti, Debsoumya
Kim, Jaehoon
Lee, Hyunwoo
Seo, Jaehyeon
Combinatorics
It is well-known that every tournament contains a Hamilton path, and every strongly connected tournament contains a Hamilton cycle. This paper establishes transversal generalizations of these classical results. For a collection $\mathbf{T}=\{T_1,\dots,T_m\}$ of not-necessarily distinct tournaments on a common vertex set $V$, an $m$-edge directed graph $\mathcal{D}$ with vertices in $V$ is called a $\mathbf{T}$-transversal if there exists a bijection $ϕ\colon E(\mathcal{D})\to [m]$ such that $e\in E(T_{ϕ(e)})$ for all $e\in E(\mathcal{D})$. We prove that for sufficiently large $m$ with $m=|V|-1$, there exists a $\mathbf{T}$-transversal Hamilton path. Moreover, if $m=|V|$ and at least $m-1$ of the tournaments $T_1,\ldots,T_m$ are assumed to be strongly connected, then there is a $\mathbf{T}$-transversal Hamilton cycle. In our proof, we utilize a novel way of partitioning tournaments which we dub $\mathbf{H}$-partition.
title Hamilton transversals in tournaments
topic Combinatorics
url https://arxiv.org/abs/2307.00912