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We prove two results regarding cycles in properly edge-colored graphs. First, we make a small improvement to the recent breakthrough work of Alon, Pokrovskiy and Sudakov who showed that every properly edge-colored complete graph $G$ on $n$…

Combinatorics · Mathematics 2017-06-16 Jozsef Balogh , Theodore Molla

An edge colored graph $G$ is rainbow edge connected if any two vertices are connected by a path whose edges have distinct colors. The rainbow connection of a connected graph $G$, denoted by $rc(G)$, is the smallest number of colors that are…

Combinatorics · Mathematics 2014-12-03 Andrzej Dudek , Alan Frieze , Charalampos Tsourakakis

We show that the threshold for having a rainbow copy of a power of a Hamilton cycle in a randomly edge colored copy of $G_{n,p}$ is within a constant factor of the uncolored threshold. Our proof requires $(1+\varepsilon)$ times the minimum…

Combinatorics · Mathematics 2024-03-04 Tolson Bell , Alan Frieze

Let $G_1,...,G_n$ be graphs on the same vertex set of size $n$, each graph with minimum degree $\delta(G_i)\ge n/2$. A recent conjecture of Aharoni asserts that there exists a rainbow Hamiltonian cycle i.e. a cycle with edge set…

Combinatorics · Mathematics 2021-02-23 Yangyang Cheng , Guanghui Wang , Yi Zhao

We consider the existence of patterned Hamilton cycles in randomly colored random graphs. Given a string $\Pi$ over a set of colors $\{1,2,\ldots,r\}$, we say that a Hamilton cycle is $\Pi$-colored if the pattern repeats at intervals of…

Combinatorics · Mathematics 2018-05-01 Michael Anastos , Alan Frieze

We consider Hamilton cycles in the random digraph $D_{n,m}$ where the orientation of edges follows a pattern other than the trivial orientation in which the edges are oriented in the same direction as we traverse the cycle. We show that if…

Combinatorics · Mathematics 2020-10-19 Alan Frieze , Xavier Perez-Gimenez , Pawel Pralat

We prove that every properly edge-colored $n$-vertex graph with average degree at least $100(\log n)^2$ contains a rainbow cycle, improving upon $(\log n)^{2+o(1)}$ bound due to Tomon. We also prove that every properly colored $n$-vertex…

Combinatorics · Mathematics 2022-11-08 Jaehoon Kim , Joonkyung Lee , Hong Liu , Tuan Tran

An edge-colored graph is rainbow if all its edges are colored with distinct colors. For a fixed graph $H$, the rainbow Tur\'an number $\mathrm{ex}^{\ast}(n,H)$ is defined as the maximum number of edges in a properly edge-colored graph on…

Combinatorics · Mathematics 2012-05-15 Shagnik Das , Choongbum Lee , Benny Sudakov

An edge-coloured cycle is rainbow if the edges have distinct colours. Let $G$ be a graph such that any $k$ vertices lie in a cycle of $G$. The $k$-rainbow cycle index of $G$, denoted by $crx_k(G)$, is the minimum number of colours required…

Combinatorics · Mathematics 2024-05-31 Henry Liu

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

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

For an edge-colored graph, a subgraph is called rainbow if all its edges have distinct colors. We show that if $G$ is an edge-colored graph of order $n$ and size $m$ using $c$ colors on its edges, and $m+c\geq \binom{n+1}{2}+k-1$ for a…

Combinatorics · Mathematics 2018-10-12 Stefan Ehard , Elena Mohr

Given a graph $G$ and a coloring of its edges, a subgraph of $G$ is called rainbow if its edges have distinct colors. The rainbow girth of an edge coloring of G is the minimum length of a rainbow cycle in G. A generalization of the famous…

Combinatorics · Mathematics 2024-09-25 Ron Aharoni , He Guo

An edge-colored multigraph $G$ is rainbow connected if every pair of vertices is joined by at least one rainbow path, i.e., a path where no two edges are of the same color. In the context of multilayered networks we introduce the notion of…

Combinatorics · Mathematics 2025-03-04 Josep Díaz , Öznur Yaşar Diner , Maria Serna , Oriol Serra

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 $\mathcal{G}=\{G_1, G_2, \ldots , G_k\}$ be a family of bipartite graphs on the same vertex set. A rainbow Hamilton path (cycle) in $\mathcal{G}$ is a path (cycle) that visits each vertex precisely once such that any two edges belong to…

Combinatorics · Mathematics 2026-03-05 Meng chen , Ruifang Liu , Qixuan Yuan

Given an $n$ vertex graph whose edges have colored from one of $r$ colors $C=\{c_1,c_2,\ldots,c_r\}$, we define the Hamilton cycle color profile $hcp(G)$ to be the set of vectors $(m_1,m_2,\ldots,m_r)\in [0,n]^r$ such that there exists a…

Combinatorics · Mathematics 2024-02-07 Debsoumya Chakraborti , Alan Frieze , Mihir Hasabnis

In a properly edge colored graph, a subgraph using every color at most once is called rainbow. In this thesis, we study rainbow cycles and paths in proper edge colorings of complete graphs, and we prove that in every proper edge coloring of…

Discrete Mathematics · Computer Science 2012-07-05 Heidi Gebauer , Frank Mousset

We first consider the following problem. We are given a fixed perfect matching $M$ of $[n]$ and we add random edges one at a time until there is a Hamilton cycle containing $M$. We show that w.h.p. the hitting time for this event is the…

Combinatorics · Mathematics 2017-05-26 Lisa Espig , Alan Frieze , Michael Krivelevich

A meta-conjecture of Coulson, Keevash, Perarnau and Yepremyan states that above the extremal threshold for a given spanning structure in a (hyper-)graph, one can find a rainbow version of that spanning structure in any suitably bounded…

Combinatorics · Mathematics 2026-02-25 Amarja Kathapurkar , Patrick Morris , Guillem Perarnau