Weak rainbow saturation numbers of graphs

Fuente: arXiv
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Main Authors: Li, Xihe, Ma, Jie, Xie, Tianying
Format: Preprint
Published: 2024
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author Li, Xihe
Ma, Jie
Xie, Tianying
author_facet Li, Xihe
Ma, Jie
Xie, Tianying
contents For a fixed graph $H$, we say that an edge-colored graph $G$ is \emph{weakly $H$-rainbow saturated} if there exists an ordering $e_1, e_2, \ldots, e_m$ of $E\left(\overline{G}\right)$ such that, for any list $c_1, c_2, \ldots, c_m$ of pairwise distinct colors from $\mathbb{N}$, the non-edges $e_i$ in color $c_i$ can be added to $G$, one at a time, so that every added edge creates a new rainbow copy of $H$. The \emph{weak rainbow saturation number} of $H$, denoted by $rwsat(n,H)$, is the minimum number of edges in a weakly $H$-rainbow saturated graph on $n$ vertices. In this paper, we show that for any non-empty graph $H$, the limit $\lim_{n\to \infty} \frac{rwsat(n, H)}{n}$ exists. This answers a question of Behague, Johnston, Letzter, Morrison and Ogden [{\it SIAM J. Discrete Math.} (2023)]. We also provide lower and upper bounds on this limit, and in particular, we show that this limit is nonzero if and only if $H$ contains no pendant edges.
format Preprint
id arxiv_https___arxiv_org_abs_2401_11525
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Weak rainbow saturation numbers of graphs
Li, Xihe
Ma, Jie
Xie, Tianying
Combinatorics
For a fixed graph $H$, we say that an edge-colored graph $G$ is \emph{weakly $H$-rainbow saturated} if there exists an ordering $e_1, e_2, \ldots, e_m$ of $E\left(\overline{G}\right)$ such that, for any list $c_1, c_2, \ldots, c_m$ of pairwise distinct colors from $\mathbb{N}$, the non-edges $e_i$ in color $c_i$ can be added to $G$, one at a time, so that every added edge creates a new rainbow copy of $H$. The \emph{weak rainbow saturation number} of $H$, denoted by $rwsat(n,H)$, is the minimum number of edges in a weakly $H$-rainbow saturated graph on $n$ vertices. In this paper, we show that for any non-empty graph $H$, the limit $\lim_{n\to \infty} \frac{rwsat(n, H)}{n}$ exists. This answers a question of Behague, Johnston, Letzter, Morrison and Ogden [{\it SIAM J. Discrete Math.} (2023)]. We also provide lower and upper bounds on this limit, and in particular, we show that this limit is nonzero if and only if $H$ contains no pendant edges.
title Weak rainbow saturation numbers of graphs
topic Combinatorics
url https://arxiv.org/abs/2401.11525