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Given a graph $H$, we say that an edge-coloured graph $G$ is $H$-rainbow saturated if it does not contain a rainbow copy of $H$, but the addition of any non-edge in any colour creates a rainbow copy of $H$. The rainbow saturation number…

Combinatorics · Mathematics 2024-04-17 Natalie Behague , Tom Johnston , Shoham Letzter , Natasha Morrison , Shannon Ogden

An edge-colored graph $F$ is {\it rainbow} if each edge of $F$ has a unique color. The {\it rainbow Tur\'an number} $\mathrm{ex}^*(n,F)$ of a graph $F$ is the maximum possible number of edges in a properly edge-colored $n$-vertex graph with…

Combinatorics · Mathematics 2020-09-02 Anastasia Halfpap , Cory Palmer

The vertex cover number of a graph is the minimum number of vertices that are needed to cover all edges. When those vertices are further required to induce a connected subgraph, the corresponding number is called the connected vertex cover…

Discrete Mathematics · Computer Science 2013-05-16 Eglantine Camby , Jean Cardinal , Samuel Fiorini , Oliver Schaudt

A tree $T$, in an edge-colored graph $G$, is called {\em a rainbow tree} if no two edges of $T$ are assigned the same color. For a vertex subset $S\in V(G)$, a tree that connects $S$ in $G$ is called an $S$-tree. A {\em $k$-rainbow…

Combinatorics · Mathematics 2013-10-10 Tingting Liu , Yumei Hu

Let $G$ be a nontrivial connected graph with an edge-coloring $c:E(G)\rightarrow \{1,2,\ldots,q\},$ $q\in \mathbb{N}$, 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 2013-08-21 Xueliang Li , Kang Yang , Yan Zhao

We study a new variant of \emph{connected coloring} of graphs based on the concept of \emph{strong} edge coloring (every color class forms an \emph{induced} matching). In particular, an edge-colored path is \emph{strongly proper} if its…

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

Given a graph on $n$ vertices and an assignment of colours to the edges, a rainbow Hamilton cycle is a cycle of length $n$ visiting each vertex once and with pairwise different colours on the edges. Similarly (for even $n$) a rainbow…

Combinatorics · Mathematics 2016-02-17 Deepak Bal , Patrick Bennett , Xavier Pérez-Giménez , Paweł Prałat

Given two graphs $G$ and $H$, the {\it rainbow number} $rb(G,H)$ for $H$ with respect to $G$ is defined as the minimum number $k$ such that any $k$-edge-coloring of $G$ contains a rainbow $H$, i.e., a copy of $H$, all of whose edges have…

Combinatorics · Mathematics 2018-09-27 Zhongmei Qin , Yongxin Lan , Yongtang Shi

Aharoni and Berger conjectured that every bipartite graph which is the union of n matchings of size n + 1 contains a rainbow matching of size n. This conjecture is a generalization of several old conjectures of Ryser, Brualdi, and Stein…

Combinatorics · Mathematics 2015-04-22 Alexey Pokrovskiy

Given a graph $H$, we say that a graph $G$ is properly rainbow $H$-saturated if: (1) There is a proper edge colouring of $G$ containing no rainbow copy of $H$; (2) For every $e \notin E(G)$, every proper edge colouring of $G+e$ contains a…

Combinatorics · Mathematics 2024-10-15 Andrew Lane , Natasha Morrison

An edge-colored graph $G$ is conflict-free connected if any two of its vertices are connected by a path which contains a color used on exactly one of its edges. The conflict-free connection number of a connected graph $G$, denoted by…

Combinatorics · Mathematics 2018-09-12 Ran Gu , Xueliang Li

An edge-colored graph $G$ is conflict-free connected if any two of its vertices are connected by a path, which contains a color used on exactly one of its edges. The conflict-free connection number of a connected graph $G$, denoted by…

Combinatorics · Mathematics 2020-12-10 Jing Wang , Meng Ji

A rainbow neighbourhood of a graph $G$ with respect to a proper colouring $\C$ of $G$ is the closed neighbourhood $N[v]$ of a vertex $v$ in $G$ such that $N[v]$ consists of vertices from all colour classes in $G$ with respect to $\C$. The…

General Mathematics · Mathematics 2017-10-03 Johan Kok , Sudev Naduvath , Orville Buelban

A path in a vertex-colored graph is a {\it vertex-proper path} if any two internal adjacent vertices differ in color. A vertex-colored graph is {\it proper vertex $k$-connected} if any two vertices of the graph are connected by $k$ disjoint…

Combinatorics · Mathematics 2015-05-20 Hui Jiang , Xueliang Li , Yingying Zhang , Yan Zhao

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

Let $G$ be an edge-colored connected graph. A path $P$ in $G$ is called a distance $\ell$-proper path if no two edges of the same color can appear with less than $\ell$ edges in between on $P$. The graph $G$ is called $(k,\ell)$-proper…

Combinatorics · Mathematics 2016-07-21 Xueliang Li , Colton Magnant , Meiqin Wei , Xiaoyu Zhu

In this paper we study the following problem proposed by Barrus, Ferrara, Vandenbussche, and Wenger. Given a graph $H$ and an integer $t$, what is $\operatorname{sat}_{t}\left(n, \mathfrak{R}{(H)}\right)$, the minimum number of edges in a…

Combinatorics · Mathematics 2019-10-24 António Girão , David Lewis , Kamil Popielarz

Given a vertex-colored graph, we say a path is a rainbow vertex path if all its internal vertices have distinct colors. The graph is rainbow vertex-connected if there is a rainbow vertex path between every pair of its vertices. In the…

Discrete Mathematics · Computer Science 2020-05-12 Paloma T. Lima , Erik Jan van Leeuwen , Marieke van der Wegen

Rainbow coloring is a special case of edge coloring, where there must be at least one path between every distinct pair of vertices that consists of different color edges. Here, we may use the same color for the adjacent edges of a graph…

Data Structures and Algorithms · Computer Science 2020-01-01 Debasis Dwibedy , Rakesh Mohanty , Arun Khamari