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Rainbow connection number, $rc(G)$, of a connected graph $G$ is the minimum number of colours needed to colour its edges, so that every pair of vertices is connected by at least one path in which no two edges are coloured the same. In this…

Combinatorics · Mathematics 2011-05-31 L. Sunil Chandran , Rogers Mathew , Deepak Rajendraprasad

In this note we examine the following random graph model: for an arbitrary graph $H$, with quadratic many edges, construct a graph $G$ by randomly adding $m$ edges to $H$ and randomly coloring the edges of $G$ with $r$ colors. We show that…

Combinatorics · Mathematics 2023-04-28 József Balogh , John Finlay , Cory Palmer

Let $G$ be an edge-coloured graph. The minimum colour degree $ \delta^c(G) $ of $G$ is the largest integer $k$ such that, for every vertex $v$, there are at least $k$ distinct colours on edges incident to $v$. We say that $G$ is properly…

Combinatorics · Mathematics 2013-12-11 Allan Lo

An edge coloring of the n-vertex complete graph K_n is a Gallai coloring if it does not contain any rainbow triangle, that is, a triangle whose edges are colored with three distinct colors. We prove that the number of Gallai colorings of…

One of the most famous results in the theory of random graphs establishes that the threshold for Hamiltonicity in the Erdos-Renyi random graph G_{n,p} is around p ~ (log n + log log n) / n. Much research has been done to extend this to…

Combinatorics · Mathematics 2011-01-04 Alan Frieze , Po-Shen Loh

A clique-coloring of a graph $G$ is a coloring of the vertices of $G$ so that no maximal clique of size at least two is monochromatic. The clique-hypergraph, $\mathcal{H}(G)$, of a graph $G$ has $V(G)$ as its set of vertices and the maximal…

Combinatorics · Mathematics 2014-08-22 Erfang Shan , Yuxiao Sun , Liying Kang

We say that an edge-coloring of a graph $G$ is proper if every pair of incident edges receive distinct colors, and is rainbow if no two edges of $G$ receive the same color. Furthermore, given a fixed graph $F$, we say that $G$ is rainbow…

Combinatorics · Mathematics 2026-02-19 Anastasia Halfpap , Bernard Lidický , Tomáš Masařík

An edge-colored graph $G$ is called \textit{rainbow} if every edge of $G$ receives a different color. Given any host graph $G$, the \textit{anti-Ramsey} number of $t$ edge-disjoint rainbow spanning trees in $G$, denoted by $r(G,t)$, is…

Combinatorics · Mathematics 2021-04-28 Linyuan Lu , Andrew Meier , Zhiyu Wang

An edge-coloring of a graph $H$ is a function $\mathcal{C}: E(H) \rightarrow \mathbb{N}$. We say that $H$ is rainbow if all edges of $H$ have different colors. Given a graph $F$, an edge-colored graph $G$ is $F$-rainbow saturated if $G$…

Combinatorics · Mathematics 2025-01-14 Yiduo Xu , Zhen He , Mei Lu

In this short note, we study pairwise edge-disjoint rainbow spanning trees in properly edge-coloured complete graphs, where a graph is rainbow if its edges have distinct colours. Brualdi and Hollingsworth conjectured that every $K_n$…

Combinatorics · Mathematics 2017-04-25 József Balogh , Hong Liu , Richard Montgomery

Let $G = (V, E)$ be a graph on $n$ vertices, and let $c: E \to P$, where $P$ is a set of colors. Let $\delta^c(G) = \min_{v \in V} \{ d^{c}(v) \}$ where $d^c(v)$ is the number of colors on edges incident to a vertex $v$ of $G$. In 2011,…

Combinatorics · Mathematics 2024-11-15 Andrzej Czygrinow , Xiaofan Yuan

A proper edge coloring of a graph $G$ with colors $1,2,\dots,t$ is called a \emph{cyclic interval $t$-coloring} if for each vertex $v$ of $G$ the edges incident to $v$ are colored by consecutive colors, under the condition that color $1$ is…

Combinatorics · Mathematics 2017-03-30 Armen S. Asratian , Carl Johan Casselgren , Petros A. Petrosyan

We obtain sufficient conditions for the emergence of spanning and almost-spanning bounded-degree {\sl rainbow} trees in various host graphs, having their edges coloured independently and uniformly at random, using a predetermined palette.…

Combinatorics · Mathematics 2021-05-25 Elad Aigner-Horev , Dan Hefetz , Abhiruk Lahiri

Let $G = (G_1, G_2, \ldots, G_m)$ be a collection of $m$ graphs on a common vertex set $V$. For a graph $H$ with vertices in $V$, we say that $G$ contains a rainbow $H$ if there is an injection $c: E(H) \to [m]$ such that for every edge $e…

Combinatorics · Mathematics 2025-12-16 Yupei Li , Ruth Luo

We prove several results on approximate decompositions of edge-coloured quasirandom graphs into rainbow spanning structures. More precisely, we say that an edge-colouring of a graph is locally $\ell$-bounded if no vertex is incident to more…

Combinatorics · Mathematics 2019-10-01 Jaehoon Kim , Daniela Kühn , Andrey Kupavskii , Deryk Osthus

Let $ H = (V,E) $ be a hypergraph. By the chromatic number of a hypergraph $ H = (V,E) $ we mean the minimum number $\chi(H)$ of colors needed to paint all the vertices in $ V $ so that any edge $ e \in E $ contains at least two vertices of…

Combinatorics · Mathematics 2011-07-12 Danila D. Cherkashin

An edge-colored graph is called rainbow if all the colors on its edges are distinct. Given a positive integer n and a graph G, the anti-Ramsey number ar(n,G) is the maximum number of colors in an edge-coloring of K_{n} with no rainbow copy…

Combinatorics · Mathematics 2022-01-12 Fangfang Wu , Shenggui Zhang , Binlong Li , Jimeng Xiao

An edge-coloring of a complete graph with a set of colors $C$ is called completely balanced if any vertex is incident to the same number of edges of each color from $C$. Erd\H{o}s and Tuza asked in $1993$ whether for any graph $F$ on $\ell$…

Combinatorics · Mathematics 2022-11-29 Maria Axenovich , Felix Christian Clemen

We call the minimum order of any complete graph so that for any coloring of the edges by $k$ colors it is impossible to avoid a monochromatic or rainbow triangle, a Mixed Ramsey number. For any graph $H$ with edges colored from the above…

Combinatorics · Mathematics 2014-03-18 Marcus Bartlett , Elliot Krop , Thuhong Nguyen , Michael Ngo , Petra President

In this paper we study the randomly edge colored graph that is obtained by adding randomly colored random edges to an arbitrary randomly edge colored dense graph. In particular we ask how many colors and how many random edges are needed so…

Combinatorics · Mathematics 2018-02-02 Michael Anastos , Alan Frieze
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