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Related papers: On the K{\L}R conjecture in random graphs

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We prove a robust version of a graph embedding theorem of Sauer and Spencer. To state this sparser analogue, we define $G(p)$ to be a random subgraph of $G$ obtained by retaining each edge of $G$ independently with probability $p \in…

Combinatorics · Mathematics 2025-07-08 Peter Allen , Julia Böttcher , Yoshiharu Kohayakawa , Mihir Neve

A classic result of Erd\H{o}s, Gy\'arf\'as and Pyber states that for every coloring of the edges of $K_n$ with $r$ colors, there is a cover of its vertex set by at most $f(r) = O(r^2 \log r)$ vertex-disjoint monochromatic cycles. In…

Combinatorics · Mathematics 2018-07-18 Dániel Korándi , Frank Mousset , Rajko Nenadov , Nemanja Škorić , Benny Sudakov

Settling a first case of a conjecture of M. Kahle on the homology of the clique complex of the random graph $G=G_{n,p}$, we show, roughly speaking, that (with high probability) the triangles of $G$ span its cycle space whenever each of its…

Probability · Mathematics 2012-07-31 Bobby DeMarco , Arran Hamm , Jeff Kahn

Given a graph $H$, let $g(n,H)$ denote the smallest $k$ for which the following holds. We can assign a $k$-colouring $f_v$ of the edge set of $K_n$ to each vertex $v$ in $K_n$ with the property that for any copy $T$ of $H$ in $K_n$, there…

Combinatorics · Mathematics 2023-04-25 Barnabás Janzer , Oliver Janzer

We study sparse hypergraphs which satisfy a mild pseudorandomness condition known as $L_p$ regularity. We prove appropriate regularity and counting lemmas, and we extend the relative removal lemma of Tao in this setting. This answers a…

Combinatorics · Mathematics 2018-02-27 Pandelis Dodos , Vassilis Kanellopoulos , Thodoris Karageorgos

We prove two conjectures in spectral extremal graph theory involving the linear combinations of graph eigenvalues. Let $\lambda_1(G)$ be the largest eigenvalue of the adjacency matrix of a graph $G$, and $\bar{G}$ be the complement of $G$.…

Combinatorics · Mathematics 2022-06-09 Lele Liu

A longstanding conjecture of Seymour states that in every oriented graph there is a vertex whose second outneighbourhood is at least as large as its outneighbourhood. In this short note we show that, for any fixed $p\in[0,1/2)$, a.a.s.…

Combinatorics · Mathematics 2024-08-12 Alberto Espuny Díaz , António Girão , Bertille Granet , Gal Kronenberg

We establish new couplings among several random graph and multigraph models related to the random regular graph $G(n,d)$, including the configuration model and unions of random perfect matchings. As a main result, we verify the…

Combinatorics · Mathematics 2025-10-27 Pu Gao , Mikhail Isaev , Xavier Perez-Gimenez

In a recent paper, Oliver Riordan shows that for $r \ge 4$ and $p$ up to and slightly larger than the threshold for a $K_r$-factor, the hypergraph formed by the copies of $K_r$ in $G(n,p)$ contains a copy of the binomial random hypergraph…

Combinatorics · Mathematics 2018-07-23 Annika Heckel

A classical theorem of Ghouila-Houri from 1960 asserts that every directed graph on $n$ vertices with minimum out-degree and in-degree at least $n/2$ contains a directed Hamilton cycle. In this paper we extend this theorem to a random…

Combinatorics · Mathematics 2014-04-21 Dan Hefetz , Angelika Steger , Benny Sudakov

We show that, for every $r, k$, there is an $n = n(r,k)$ so that any $r$-coloring of the edges of the complete graph on $[n]$ will yield a monochromatic complete subgraph on vertices ${a + \sum_{i \in I} d_i \mid I \subseteq [k]}$ for some…

Combinatorics · Mathematics 2012-03-01 Andy Parrish

We present a variant of a universality result of R\"odl [On universality of graphs with uniformly distributed edges, Discrete Math. 59 (1986), no. 1-2, 125-134] for sparse, $3$-uniform hypergraphs contained in strongly jumbled hypergraphs.…

Combinatorics · Mathematics 2017-11-01 Yoshiharu Kohayakawa , Guilherme O. Mota , Mathias Schacht , Anusch Taraz

Majority dynamics on a graph $G$ is a deterministic process such that every vertex updates its $\pm 1$-assignment according to the majority assignment on its neighbor simultaneously at each step. Benjamini, Chan, O'Donnel, Tamuz and Tan…

Combinatorics · Mathematics 2024-02-09 Debsoumya Chakraborti , Jeong Han Kim , Joonkyung Lee , Tuan Tran

The Blow-up Lemma established by Koml\'os, S\'ark\"ozy, and Szemer\'edi in 1997 is an important tool for the embedding of spanning subgraphs of bounded maximum degree. Here we prove several generalisations of this result concerning the…

Combinatorics · Mathematics 2013-05-10 Julia Böttcher , Yoshiharu Kohayakawa , Anusch Taraz , Andreas Würfl

Hadwiger's conjecture asserts that every graph with chromatic number $t$ contains a complete minor of order $t$. Given integers $n \ge 2k+1 \ge 5$, the Kneser graph $K(n, k)$ is the graph with vertices the $k$-subsets of an $n$-set such…

Combinatorics · Mathematics 2015-12-01 Guangjun Xu , Sanming Zhou

A graph is said to contain $K_k$ (a clique of size $k$) as a weak immersion if it has $k$ vertices, pairwise connected by edge-disjoint paths. In 1989, Lescure and Meyniel made the following conjecture related to Hadwiger's conjecture:…

Combinatorics · Mathematics 2025-10-08 Jacob Fox , Janos Pach , Andrew Suk

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

In their celebrated paper [Ramsey-Type Theorems, Discrete Appl. Math. 25 (1989) 37-52], Erd\H{o}s and Hajnal asked the following: is it true, that for any finite graph H there exists a constant c(H) such that for any finite graph G, if G…

Logic · Mathematics 2017-08-21 Gábor Sági

We study robust versions of properties of $(n,d,\lambda)$-graphs, namely, the property of a random sparsification of an $(n,d,\lambda)$-graph, where each edge is retained with probability $p$ independently. We prove such results for the…

Combinatorics · Mathematics 2025-11-04 Yaobin Chen , Yu Chen , Jie Han , Jingwen Zhao

Klimo\v{s}ov\'a, Piguet, and Rozho\v{n} conjectured that any graph with minimum degree $k/2$ and sufficiently many vertices of degree $k$ should contain all trees with $k$ edges. We prove an asymptotic version of this conjecture for dense…

Combinatorics · Mathematics 2026-03-19 Akbar Davoodi , Diana Piguet , Hanka Řada , Nicolás Sanhueza-Matamala