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The multicolor Ramsey number problem asks, for each pair of natural numbers $\ell$ and $t$, for the largest $\ell$-coloring of a complete graph with no monochromatic clique of size $t$. Recent works of Conlon-Ferber and Wigderson have…

Combinatorics · Mathematics 2021-11-23 Will Sawin

We study a generalization of a famous result of Goodman and establish that asymptotically at least a $1/256$ fraction of all triangles needs to be monochromatic in any four-coloring of the edges of a complete graph. We also show that any…

Combinatorics · Mathematics 2023-12-14 Aldo Kiem , Sebastian Pokutta , Christoph Spiegel

Consider a game played on the edge set of the infinite clique by two players, Builder and Painter. In each round, Builder chooses an edge and Painter colours it red or blue. Builder wins by creating either a red copy of $G$ or a blue copy…

Combinatorics · Mathematics 2014-10-21 Joanna Cyman , Tomasz Dzido , John Lapinskas , Allan Lo

Bal and DeBiasio [Partitioning random graphs into monochromatic components, Electron. J. Combin. 24 (2017), Paper 1.18] put forward a conjecture concerning the threshold for the following Ramsey-type property for graphs $G$: every…

Combinatorics · Mathematics 2019-02-20 Yoshiharu Kohayakawa , Guilherme Oliveira Mota , Mathias Schacht

The online Ramsey game for graphs $G$ and $H$ is played on the infinite complete graph $K_\mathbb{N}$. Each round, Builder chooses an edge, and Painter colors it red or blue. The online Ramsey number $\tilde{r}(G,H)$ is the smallest integer…

Combinatorics · Mathematics 2026-04-21 Sam Beilis , Israel R. Curbelo

Vizing's theorem states that any graph of maximum degree $\Delta$ can be properly edge colored with at most $\Delta+1$ colors. In the online setting, it has been a matter of interest to find an algorithm that can properly edge color any…

Data Structures and Algorithms · Computer Science 2024-10-30 Aditi Dudeja , Rashmika Goswami , Michael Saks

Given two graph families $\mathcal H_1$ and $\mathcal H_2$, a size Ramsey game is played on the edge set of $K_\mathbb{N}$. In every round, Builder selects an edge and Painter colours it red or blue. Builder is trying to force Painter to…

Combinatorics · Mathematics 2022-11-02 Grzegorz Adamski , Małgorzata Bednarska-Bzdęga

Given a graph G and an integer k, two players take turns coloring the vertices of G one by one using k colors so that neighboring vertices get different colors. The first player wins iff at the end of the game all the vertices of $G$ are…

Combinatorics · Mathematics 2018-06-12 Alan Frieze , Simi Haber , Mikhail Lavrov

The network coloring game has been proposed in the literature of social sciences as a model for conflict-resolution circumstances. The players of the game are the vertices of a graph with $n$ vertices and maximum degree $\Delta$. The game…

Discrete Mathematics · Computer Science 2022-04-01 Nikolaos Fryganiotis , Symeon Papavassiliou , Christos Pelekis

We present a refinement of the classical alteration method for constructing $H$-free graphs: for suitable edge-probabilities $p$, we show that removing all edges in $H$-copies of the binomial random graph $G_{n,p}$ does not significantly…

Combinatorics · Mathematics 2023-12-20 He Guo , Lutz Warnke

Ramsey's theorem, in the version of Erd\H{o}s and Szekeres, states that every 2-coloring of the edges of the complete graph on {1, 2,...,n} contains a monochromatic clique of order 1/2\log n. In this paper, we consider two well-studied…

Combinatorics · Mathematics 2019-12-19 David Conlon , Jacob Fox , Benny Sudakov

Starting from a complete graph on $n$ vertices, repeatedly delete the edges of a uniformly chosen triangle. This stochastic process terminates once it arrives at a triangle-free graph, and the fundamental question is to estimate the final…

Combinatorics · Mathematics 2012-06-11 Tom Bohman , Alan Frieze , Eyal Lubetzky

We give asymptotically optimal constructions in generalized Ramsey theory using results about conflict-free hypergraph matchings. For example, we present an edge-coloring of $K_{n,n}$ with $2n/3 + o(n)$ colors such that each $4$-cycle…

Combinatorics · Mathematics 2022-08-29 Felix Joos , Dhruv Mubayi

The Erd\H{o}s-Gy\'arf\'as number $f(n, p, q)$ is the smallest number of colors needed to color the edges of the complete graph $K_n$ so that all of its $p$-clique spans at least $q$ colors. In this paper we improve the best known upper…

Combinatorics · Mathematics 2023-02-10 Patrick Bennett , Andrzej Dudek , Sean English

Given two graphs $G$ and $H$, we investigate for which functions $p=p(n)$ the random graph $G_{n,p}$ (the binomial random graph on $n$ vertices with edge probability $p$) satisfies with probability $1-o(1)$ that every red-blue-coloring of…

Combinatorics · Mathematics 2016-02-15 Yoshiharu Kohayakawa , Mathias Schacht , Reto Spöhel

For two graphs $B$ and $H$ the strong Ramsey game $\mathcal{R}(B,H)$ on the board $B$ and with target $H$ is played as follows. Two players alternately claim edges of $B$. The first player to build a copy of $H$ wins. If none of the players…

Combinatorics · Mathematics 2020-03-11 Stefan David , Ivailo Hartarsky , Marius Tiba

The strong Ramsey game $R(\mathcal{B}, H)$ is a two-player game played on a graph $\mathcal{B}$, referred to as the board, with a target graph $H$. In this game, two players, $P_1$ and $P_2$, alternately claim unclaimed edges of…

Combinatorics · Mathematics 2025-01-28 Jiangdong Ai , Jun Gao , Zixiang Xu , Xin Yan

Given a graph $G$, its $2$-color Tur\'{a}n number $\mathrm{ex}^{(2)}(n,G)$ is the largest number of edges in an $n$-vertex graph whose edges can be colored with two colors avoiding a monochromatic copy of $G$. Let…

Combinatorics · Mathematics 2024-09-13 Maria Axenovich , Simon Gaa , Dingyuan Liu

R\"odl and Ruci\'nski (1990) established Ramsey's theorem for random graphs. In particular, for fixed integers $r$, $\ell\geq 2$ they showed that $\hat p_{K_\ell,r}(n)=n^{-\frac{2}{\ell+1}}$ is a threshold for the Ramsey property that every…

Combinatorics · Mathematics 2025-07-31 Nina Kamčev , Mathias Schacht

In 1995 Kim famously proved the Ramsey bound R(3,t) \ge c t^2/\log t by constructing an n-vertex graph that is triangle-free and has independence number at most C \sqrt{n \log n}. We extend this celebrated result, which is best possible up…

Combinatorics · Mathematics 2021-04-06 He Guo , Lutz Warnke