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Let $G$ be a nontrivial edge-colored connected graph. An edge-cut $R$ of $G$ is called a rainbow cut if no two edges of it are colored the same. An edge-colored graph $G$ is rainbow disconnected if for every two vertices $u$ and $v$, there…

Combinatorics · Mathematics 2018-10-24 Xuqing Bai , Renying Chang , Xueliang Li

A path in an edge-colored graph $G$, where adjacent edges may be colored the same, is called a rainbow path if no two edges of $G$ are colored the same. For a $\kappa$-connected graph $G$ and an integer $k$ with $1\leq k\leq \kappa$, the…

Combinatorics · Mathematics 2009-06-23 Xueliang Li , Yuefang Sun

A subgraph of an edge-coloured complete graph is called rainbow if all its edges have different colours. In 1980 Hahn conjectured that every properly edge-coloured complete graph $K_n$ has a rainbow Hamiltonian path. Although this…

Combinatorics · Mathematics 2016-08-26 Noga Alon , Alexey Pokrovskiy , Benny Sudakov

A path in an edge-colored graph $G$, where adjacent edges may have the same color, is called a rainbow path if no two edges of the path are colored the same. The rainbow connection number $rc(G)$ of $G$ is the minimum integer $i$ for which…

Combinatorics · Mathematics 2010-12-06 Hengzhe Li , Xueliang Li , Sujuan Liu

A total-colored graph is a graph $G$ such that both all edges and all vertices of $G$ are colored. A path in a total-colored graph $G$ is a total rainbow path if its edges and internal vertices have distinct colors. A total-colored graph…

Combinatorics · Mathematics 2015-01-09 Hui Jiang , Xueliang Li , Yingying Zhang

Let $k$ be a positive integer, and $G$ be a $k$-connected graph. An edge-coloured path is \emph{rainbow} if all of its edges have distinct colours. The \emph{rainbow $k$-connection number} of $G$, denoted by $rc_k(G)$, is the minimum number…

Combinatorics · Mathematics 2020-09-08 Shinya Fujita , Henry Liu , Boram Park

Let $G$ be a nontrivial connected graph with an edge-coloring $c: E(G)\rightarrow \{1,2,...,q\},$ $q \in \mathbb{N}$, where adjacent edges may be colored the same. A tree $T$ in $G$ is a $rainbow tree$ if no two edges of $T$ receive the…

Combinatorics · Mathematics 2013-07-04 Lily Chen , Xueliang Li , Kang Yang , Yan Zhao

A subgraph of an edge-coloured graph is called rainbow if all its edges have distinct colours. The study of rainbow subgraphs goes back more than two hundred years to the work of Euler on Latin squares. Since then rainbow structures have…

Combinatorics · Mathematics 2018-12-11 Richard Montgomery , Alexey Pokrovskiy , Benny Sudakov

Given a family $\mathcal G$ of graphs on a common vertex set $X$, we say that $\mathcal G$ is rainbow connected if for every vertex pair $u,v \in X$, there exists a path from $u$ to $v$ that uses at most one edge from each graph in…

Combinatorics · Mathematics 2021-07-15 Peter Bradshaw , Bojan Mohar

A \textit{rainbow subgraph} of an edge-colored graph is a subgraph whose edges have distinct colors. The \textit{color degree} of a vertex $v$ is the number of different colors on edges incident to $v$. We show that if $n$ is large enough…

Combinatorics · Mathematics 2012-04-17 Alexandr Kostochka , Florian Pfender , Matthew Yancey

The {\em rainbow vertex-connection number}, $rvc(G)$, of a connected graph $G$ is the minimum number of colors needed to color its vertices such that every pair of vertices is connected by at least one path whose internal vertices have…

Combinatorics · Mathematics 2011-10-27 Xueliang Li , Sujuan Liu

A tree in an edge colored graph is said to be a rainbow tree if no two edges on the tree share the same color. Given two positive integers $k$, $\ell$ with $k\geq 3$, the \emph{$(k,\ell)$-rainbow index} $rx_{k,\ell}(G)$ of $G$ is the…

Combinatorics · Mathematics 2013-10-21 Qingqiong Cai , Xueliang Li , Jiangli Song

Let $\mathbf{G}=\{G_1,\dots,G_{n-1}\}$ be a collection of not necessarily distinct $n$-vertex graphs with the same vertex set $V$. A path $P$ with $V(P)\subseteq V$ and $|E(P)|\leq n-1$ is rainbow in $\mathbf{G}$, if there exists an…

Combinatorics · Mathematics 2026-05-26 Menghan Ma , Lihua You , Xiaoxue Zhang

Let $G$ be a connected graph. The \emph{rainbow connection number $rc(G)$} of a graph $G$ was recently introduced by Chartrand et al. Li et al. proved that for every bridgeless graph $G$ with diameter 2, $rc(G)\leq 5$. They gave examples…

Combinatorics · Mathematics 2011-09-26 Jiuying Dong , Xueliang Li

Let $G$ be a finite group, the enhanced power graph of $G$, denoted by $\Gamma_G^e$, is the graph with vertex set $G$ and two vertices $x,y$ are edge connected in $\Gamma_{G}^e$ if there exist $z\in G$ such that $x,y\in\langle z\rangle$.…

Combinatorics · Mathematics 2017-08-28 Luis A. Dupont , Daniel G. Mendoza , Miriam Rodríguez

A path in an edge-colored graph $G$, where adjacent edges may have the same color, is called rainbow if no two edges of the path are colored the same. The rainbow connection number $rc(G)$ of $G$ is the smallest integer $k$ for which there…

Combinatorics · Mathematics 2011-10-14 Hengzhe Li , Xueliang Li , Yuefang Sun

A subgraph of an edge-colored graph is called \emph{rainbow} if all of its edges have distinct colors. There has been much research on the topic of finding a large rainbow matching in a properly edge-colored graph, where a proper…

Combinatorics · Mathematics 2026-05-28 Debsoumya Chakraborti , Po-Shen Loh

We present a edge-coloured analogue of the duality theorem for transitive tournaments and directed paths. Given a edge-coloured path $P$ whose edges alternate blue and red, we construct a edge-coloured graph $D$ so that for any…

Combinatorics · Mathematics 2022-08-29 Kyle Booker , Richard C Brewster

For a given $\delta \in (0,1)$, the randomly perturbed graph model is defined as the union of any $n$-vertex graph $G_0$ with minimum degree $\delta n$ and the binomial random graph $\mathbf{G}(n,p)$ on the same vertex set. Moreover, we say…

Combinatorics · Mathematics 2025-11-10 Kyriakos Katsamaktsis , Shoham Letzter , Amedeo Sgueglia

Let $G$ be a nontrivial edge-colored connected graph. An edge-cut $R$ of $G$ is called a {\it rainbow edge-cut} if no two edges of $R$ are colored with the same color. For two distinct vertices $u$ and $v$ of $G$, if an edge-cut separates…

Combinatorics · Mathematics 2020-09-08 Xuqing Bai , Xueliang Li
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