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Related papers: Improved Bounds on Rainbow $k$-partite Matchings

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Let $n$ be a sufficiently large integer with $n\equiv 0\pmod 4$ and let $F_i \subseteq{[n]\choose 4}$ where $i\in [n/4]$. We show that if each vertex of $F_i$ is contained in more than ${n-1\choose 3}-{3n/4\choose 3}$ edges, then $\{F_1,…

Combinatorics · Mathematics 2021-05-19 Hongliang Lu , Yan Wang , Xingxing Yu

In this work, we investigate the fewest number of colors needed to guarantee a rainbow solution to the equation $x_1 + x_2 = k x_3$ in $\mathbb{Z}_n$. This value is called the Rainbow number and is denoted by $rb(\mathbb{Z}_n, k)$ for…

Combinatorics · Mathematics 2018-09-13 Erin Bevilacqua , Samuel King , Jürgen Kritschgau , Michael Tait , Suzannah Tebon , Michael Young

Given a graph $G$, let $f_{G}(n,m)$ be the minimal number $k$ such that every $k$ independent $n$-sets in $G$ have a rainbow $m$-set. Let $\mathcal{D}(2)$ be the family of all graphs with maximum degree at most two. Aharoni et al. (2019)…

Combinatorics · Mathematics 2021-08-24 Yue Ma , Xinmin Hou , Jun Gao , Boyuan Liu , Zhi Yin

Consider the set $\{1,2,\dots,n\} = [n]$ and an equation $eq$. The rainbow number of $[n]$ for $eq$, denoted $\operatorname{rb}([n],eq)$, is the smallest number of colors such that for every exact $\operatorname{rb}([n], eq)$-coloring of…

Combinatorics · Mathematics 2020-06-09 Kean Fallon , Colin Giles , Hunter Rehm , Simon Wagner , Nathan Warnberg

For every even positive integer $k\ge 4$ let $f(n,k)$ denote the minimim number of colors required to color the edges of the $n$-dimensional cube $Q_n$, so that the edges of every copy of $k$-cycle $C_k$ receive $k$ distinct colors.…

Combinatorics · Mathematics 2012-12-10 Dhruv Mubayi , Randall Stading

A rainbow matching for (not necessarily distinct) sets F_1,...,F_k of hypergraph edges is a matching consisting of k edges, one from each F_i. The aim of the paper is twofold - to put order in the multitude of conjectures that relate to…

Combinatorics · Mathematics 2013-05-28 Ron Aharoni , Pierre Charbit , David Howard

Let $F(n,k)$ ($f(n,k)$) denote the maximum possible size of the smallest color class in a (partial) $k$-coloring of the Boolean lattice $B_n$ that does not admit a rainbow antichain of size $k$. The value of $F(n,3)$ and $f(n,2)$ has been…

Combinatorics · Mathematics 2018-12-24 Balázs Patkós

Aharoni and Howard, and, independently, Huang, Loh, and Sudakov proposed the following rainbow version of Erd\H{o}s matching conjecture: For positive integers $n,k,m$ with $n\ge km$, if each of the families $F_1,\ldots, F_m\subseteq…

Combinatorics · Mathematics 2021-09-30 Jun Gao , Hongliang Lu , Jie Ma , Xingxing Yu

Let [n]=\{1,\,2,...,\,n\} be colored in k colors. A rainbow AP(k) in [n] is a k term arithmetic progression whose elements have diferent colors. Conlon, Jungic and Radoicic [10] had shown that there exists an equinumerous 4-coloring of [4n]…

Combinatorics · Mathematics 2025-02-04 Subhajit Jana , Pratulananda Das

The Rainbow k-Coloring problem asks whether the edges of a given graph can be colored in $k$ colors so that every pair of vertices is connected by a rainbow path, i.e., a path with all edges of different colors. Our main result states that…

Data Structures and Algorithms · Computer Science 2016-02-19 Łukasz Kowalik , Juho Lauri , Arkadiusz Socała

An edge-coloured cycle is $rainbow$ if all edges of the cycle have distinct colours. For $k\geq 1$, let $\mathcal{F}_{k}$ denote the family of all graphs with the property that any $k$ vertices lie on a cycle. For $G\in \mathcal{F}_{k}$, a…

Combinatorics · Mathematics 2018-10-09 Shasha Li , Yongtang Shi , Jianhua Tu , Yan Zhao

Let $n, r, s$ be three positive integers such that $n\geq 2s+5$. Let $K_r$ denote the complete graph of order $r$. Given a graph $F$, the anti-Ramsey number $ar(n,F)$ is defined as the minimum number $C$ such that any edge-coloring of $K_n$…

Combinatorics · Mathematics 2026-04-14 Xuechun Zhang , Hongliang Lu

A perfect matching M in an edge-colored complete bipartite graph K_{n,n} is rainbow if no pair of edges in M have the same color. We obtain asymptotic enumeration results for the number of rainbow matchings in terms of the maximum number of…

Combinatorics · Mathematics 2011-04-15 Guillem Perarnau , Oriol Serra

Given a graph $G$ and a subgraph $H$ of $G$, let $rb(G,H)$ be the minimum number $r$ for which any edge-coloring of $G$ with $r$ colors has a rainbow subgraph $H$. The number $rb(G,H)$ is called the rainbow number of $H$ with respect to…

Combinatorics · Mathematics 2007-11-20 Xueliang Li , Zhixia Xu

A conjecture of the first two authors is that $n$ matchings of size $n$ in any graph have a rainbow matching of size $n-1$. We prove a lower bound of $\frac{2}{3}n-1$, improving on the trivial $\frac{1}{2}n$, and an analogous result for…

Combinatorics · Mathematics 2021-10-08 Ron Aharoni , Eli Berger , Maria Chudnovsky , Shira Zerbib

Let $n_1,\dots,n_\ell,k_1,\dots,k_\ell$ be integers and let $V_1,\dots,V_\ell$ be disjoint sets with $|V_i|=n_i$ for $i=1,\dots,\ell$. Define $\sqcup_{i=1}^\ell \binom{V_i}{k_i}$ as the collection of all subsets $F$ of $\cup_{i=1}^\ell V_i$…

Combinatorics · Mathematics 2021-11-09 Jian Wang , Jie You

Colour the edges of the complete graph with vertex set $\{1, 2, \dotsc, n\}$ with an arbitrary number of colours. What is the smallest integer $f(l,k)$ such that if $n > f(l,k)$ then there must exist a monotone monochromatic path of length…

Combinatorics · Mathematics 2023-06-02 António Girão , Freddie Illingworth , Lukas Michel , Michael Savery , Alex Scott

A hypergraph $H$ is properly colored if for every vertex $v\in V(H)$, all the edges incident to $v$ have distinct colors. In this paper, we show that if $H_{1}$, \cdots, $H_{s}$ are properly-colored $k$-uniform hypergraphs on $n$ vertices,…

Combinatorics · Mathematics 2018-08-16 Hao Huang , Tong Li , Guanghui Wang

Let $f_r(k)$ be the smallest positive integer $n$ such that every $r$-coloring of $\{1,2,...,n\}$ has a monochromatic solution to the nonlinear equation \[1/x_1+\cdots+1/x_k=1/y,\] where $x_1,...,x_k$ are not necessarily distinct. Brown and…

Combinatorics · Mathematics 2024-06-26 Collier Gaiser

A natural question, inspired by the famous Ryser-Brualdi-Stein Conjecture, is to determine the largest positive integer $g(r,n)$ such that every collection of $n$ matchings, each of size $n$, in an $r$-partite $r$-uniform hypergraph…

Combinatorics · Mathematics 2025-01-07 Candida Bowtell , Andrea Freschi , Gal Kronenberg , Jun Yan