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Related papers: Rainbow powers of a Hamilton cycle in G(n,p)

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We consider how many random edges need to be added to a graph of order $n$ with minimum degree $\alpha n$ in order that it contains the square of a Hamilton cycle w.h.p..

Combinatorics · Mathematics 2017-10-10 Patrick Bennett , Andrzej Dudek , Alan Frieze

We study Hamiltonicity in random subgraphs of the hypercube $\mathcal{Q}^n$. Our first main theorem is an optimal hitting time result. Consider the random process which includes the edges of $\mathcal{Q}^n$ according to a uniformly chosen…

Combinatorics · Mathematics 2022-08-16 Padraig Condon , Alberto Espuny Díaz , António Girão , Daniela Kühn , Deryk Osthus

Given a coloring of the edges of a multi-hypergraph, a rainbow t-matching is a collection of t disjoint edges, each having a different color. In this note we study the problem of finding a rainbow $t$-matching in an r-partite r-uniform…

Combinatorics · Mathematics 2012-11-06 Roman Glebov , Benny Sudakov , Tibor Szabó

We investigate the existence of powers of Hamiltonian cycles in graphs with large minimum degree to which some additional edges have been added in a random manner. For all integers $k\geq1$, $r\geq 0$, and $\ell\geq (r+1)r$, and for any…

Combinatorics · Mathematics 2021-04-08 Sylwia Antoniuk , Andrzej Dudek , Christian Reiher , Andrzej Ruciński , Mathias Schacht

Consider a directed analogue of the random graph process on $n$ vertices, where the $n(n-1)$ edges are ordered uniformly at random and revealed one at a time. It is known that w.h.p.\@ the first digraph in this process with both in-degree…

Combinatorics · Mathematics 2018-03-26 Michael Anastos , Joseph Briggs

For a digraph $G$ and $v \in V(G)$, let $\delta^+(v)$ be the number of out-neighbors of $v$ in $G$. The Caccetta-H\"{a}ggkvist conjecture states that for all $k \ge 1$, if $G$ is a digraph with $n = |V(G)|$ such that $\delta^+(v) \ge k$ for…

Combinatorics · Mathematics 2023-08-11 Patrick Hompe , Sophie Spirkl

In an edge-colored graph $G$, a rainbow clique $K_k$ is a $k$-complete subgraph in which all the edges have distinct colors. Let $e(G)$ and $c(G)$ be the number of edges and colors in $G$, respectively. In this paper, we show that for any…

Combinatorics · Mathematics 2023-08-16 Xiao-Chuan Liu , Danni Peng , Xu Yang

For a fixed graph $H$, what is the smallest number of colours $C$ such that there is a proper edge-colouring of the complete graph $K_n$ with $C$ colours containing no two vertex-disjoint colour-isomorphic copies, or repeats, of $H$? We…

Combinatorics · Mathematics 2021-06-28 David Conlon , Mykhaylo Tyomkyn

Let $H_r(n,p)$ denote the maximum number of Hamiltonian cycles in an $n$-vertex $r$-graph with density $p \in (0,1)$. The expected number of Hamiltonian cycles in the random $r$-graph model $G_r(n,p)$ is $E(n,p)=p^n(n-1)!/2$ and in the…

Combinatorics · Mathematics 2022-01-04 Raphael Yuster

The clique chromatic number of a graph is the smallest number of colors in a vertex coloring so that no maximal clique is monochromatic. In 2016 McDiarmid, Mitsche and Pralat noted that around p \approx n^{-1/2} the clique chromatic number…

Combinatorics · Mathematics 2023-05-30 Lyuben Lichev , Dieter Mitsche , Lutz Warnke

We study the following rainbow version of subgraph containment problems in a family of (hyper)graphs, which generalizes the classical subgraph containment problems in a single host graph. For a collection $\textbf{G}=\{G_1, G_2,\ldots,…

Combinatorics · Mathematics 2023-10-05 Yangyang Cheng , Jie Han , Bin Wang , Guanghui Wang

We find the threshold for the existence of a collection of edge disjoint copies of $K_r$ that form a cyclic structure and span all vertices of $G_{n,p}$. We use a recent result of Riordan to give a two line proof of the main result.

Combinatorics · Mathematics 2020-06-01 Alan Frieze

We study an anti-Ramsey extension of the classical Corr\'{a}di--Hajnal Theorem: how many colors are needed to color the complete graph on $n$ vertices in order to guarantee a rainbow copy of $t K_{3}$, that is, $t$ vertex-disjoint…

Combinatorics · Mathematics 2025-10-07 Deng Jinghua , Hou Jianfeng , Hu caiyun , Liu xizhi

Let $C_n^k$ be the $k$-th power of a cycle on $n$ vertices (i.e. the vertices of $C_n^k$ are those of the $n$-cycle, and two vertices are connected by an edge if their distance along the cycle is at most $k$). For each vertex draw uniformly…

Combinatorics · Mathematics 2007-05-23 Michael Krivelevich , Asaf Nachmias

Given graphs $G$ and $H$ and a positive integer $k$, the \emph{Gallai-Ramsey number}, denoted by $gr_{k}(G : H)$ is defined to be the minimum integer $n$ such that every coloring of $K_{n}$ using at most $k$ colors will contain either a…

Combinatorics · Mathematics 2019-02-05 Xihe Li , Pierre Besse , Colton Magnant , Ligong Wang , Noah Watts

In Euclidean Ramsey Theory usually we are looking for monochromatic configurations in the Euclidean space, whose points are colored with a fixed number of colors. In the canonical version, the number of colors is arbitrary, and we are…

Combinatorics · Mathematics 2026-02-03 Panna Gehér , Arsenii Sagdeev , Géza Tóth

In this paper we prove that the limiting distribution of the Chromatic number of a random graph $\mathcal{G}_{n,p}$, with fixed edge-probability $p$, after appropriate centering and scaling is Normal, when the number of vertices $n$, goes…

Statistics Theory · Mathematics 2015-08-11 Ali Rejali , Farkhondeh Sajadi

The square $G^2$ of a graph $G$ is the graph on $V(G)$ with a pair of vertices $uv$ an edge whenever $u$ and $v$ have distance $1$ or $2$ in $G$. Given graphs $G$ and $H$, the Ramsey number $R(G,H)$ is the minimum $N$ such that whenever the…

Combinatorics · Mathematics 2025-07-18 Peter Allen , Domenico Mergoni Cecchelli , Barnaby Roberts , Jozef Skokan

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

For a digraph $G$ and $v \in V(G)$, let $\delta^+(v)$ be the number of out-neighbors of $v$ in $G$. The Caccetta-H\"{a}ggkvist conjecture states that for all $k \ge 1$, if $G$ is a digraph with $n = |V(G)|$ such that $\delta^+(v) \ge k$ for…

Combinatorics · Mathematics 2021-10-04 Patrick Hompe , Petra Pelikanova , Aneta Pokorna , Sophie Spirkl
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