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Related papers: Extremal results in random graphs

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For two graphs $G$ and $F$, the extremal number of $F$ in $G$, denoted by {ex}$(G,F)$, is the maximum number of edges in a spanning subgraph of $G$ not containing $F$ as a subgraph. Determining {ex}$(K_n,F)$ for a given graph $F$ is a…

Discrete Mathematics · Computer Science 2023-05-25 Junxue Zhang

We systematically study a natural problem in extremal graph theory, to minimize the number of edges in a graph with a fixed number of vertices, subject to a certain local condition: each vertex must be in a copy of a fixed graph $H$. We…

Combinatorics · Mathematics 2020-06-24 Debsoumya Chakraborti , Po-Shen Loh

The Tur\'{a}n number of a graph $H$, $ex(n,H)$, is the maximum number of edges in any graph of order $n$ which does not contain $H$ as a subgraph. Lidick\'{y}, Liu and Palmer determined $ex(n, F_m)$ for $n$ sufficiently large and proved…

Combinatorics · Mathematics 2016-11-04 Long-Tu Yuan , Xiao-Dong Zhang

The classic extremal problem is that of computing the maximum number of edges in an $F$-free graph. In the case where $F=K_{r+1}$, the extremal number was determined by Tur\'an. Later results, known as supersaturation theorems, proved that…

Combinatorics · Mathematics 2024-09-24 Jonathan Cutler , JD Nir , A. J. Radcliffe

An ordered $r$-matching is an $r$-uniform hypergraph matching equipped with an ordering on its vertices. These objects can be viewed as natural generalisations of $r$-dimensional orders. The theory of ordered 2-matchings is well-developed…

Combinatorics · Mathematics 2025-03-19 Michael Anastos , Zhihan Jin , Matthew Kwan , Benny Sudakov

The Tur\'an number $\text{ex}(n,H)$ of a graph $H$ is the maximal number of edges in an $H$-free graph on $n$ vertices. In $1983$ Chung and Erd\H{o}s asked which graphs $H$ with $e$ edges minimize $\text{ex}(n,H)$. They resolved this…

Combinatorics · Mathematics 2023-06-22 Matija Bucić , Nemanja Draganić , Benny Sudakov

In this paper, we apply the Turan sieve and the simple sieve developed by R. Murty and the first author to study problems in random graph theory. In particular, we obtain upper and lower bounds on the probability of a graph on n vertices…

Number Theory · Mathematics 2021-02-22 Yu-Ru Liu , J. C. Saunders

This paper is motivated by the question of how global and dense restriction sets in results from extremal combinatorics can be replaced by less global and sparser ones. The result we consider here as an example is Turan's theorem, which…

Combinatorics · Mathematics 2017-07-31 Peter Allen , Julia Böttcher , Jan Hladký , Diana Piguet

For a positive integer $k$, a graph property $\mathcal{H}$, and a graph parameter $\mathcal{P}$, let $\operatorname{ex}_{\mathcal{P}}(n, \mathcal{H}; \delta \geq k)$ denote the maximum value of $\mathcal{P}$ over all $n$-vertex graphs with…

Combinatorics · Mathematics 2026-04-02 Xu Liu , Bo Ning , Tao Wang

The well-known Erd\H{o}s-Gallai Theorem gave the Tur\'an number of paths. Bushaw and Kettle generalized this result to consider the Tur\'an number of disjoint paths. Since then, many studies are focused on the Tur\'an number of linear…

Combinatorics · Mathematics 2026-01-27 Xiamiao Zhao , Yiyan Zhan , Mei Lu

We survey recent advances in the theory of graph and hypergraph decompositions, with a focus on extremal results involving minimum degree conditions. We also collect a number of intriguing open problems, and formulate new ones.

Combinatorics · Mathematics 2021-06-28 Stefan Glock , Daniela Kühn , Deryk Osthus

We study the uniqueness of optimal solutions to extremal graph theory problems. Lovasz conjectured that every finite feasible set of subgraph density constraints can be extended further by a finite set of density constraints so that the…

Combinatorics · Mathematics 2020-08-26 Andrzej Grzesik , Daniel Král' , László Miklós Lovász

Infinite generalizations of theorems in finite combinatorics were initiated by Erd\H{o}s due to his famous Erd\H{o}s-Menger conjecture (now known as the Aharoni-Berger theorem) that extends Menger's theorem to infinite graphs in a…

Combinatorics · Mathematics 2023-11-14 Attila Joó

For fixed graphs $H$ and $F$, the \emph{generalized Tur\'an number} $\mathrm{ex}(n,H,F)$ is the maximum possible number of copies of a subgraph $H$ in an $n$-vertex $F$-free graph. This article is a survey of this extremal function whose…

Combinatorics · Mathematics 2025-06-05 Dániel Gerbner , Cory Palmer

Generalized Tur\'an problems have been a central topic of study in extremal combinatorics throughout the last few decades. One such problem, maximizing the number of cliques of a fixed order in a graph with fixed number of vertices and…

Combinatorics · Mathematics 2021-06-10 Debsoumya Chakraborti , Da Qi Chen

In this paper extremal problems for uniform hypergraphs are studied in the general setting of hereditary properties. It turns out that extremal problems about edges are particular cases of a general analyic problem about a recently…

Combinatorics · Mathematics 2013-05-14 Vladimir Nikiforov

One of the cornerstones of extremal graph theory is a result of F\"uredi, later reproved and given due prominence by Alon, Krivelevich and Sudakov, saying that if $H$ is a bipartite graph with maximum degree $r$ on one side, then there is a…

Combinatorics · Mathematics 2019-02-12 David Conlon , Joonkyung Lee

The uniform Tur\'an density $\pi_{u}(F)$ of a $3$-uniform hypergraph (or $3$-graph) $F$ is the supremum of all $d$ such that there exist infinitely many $F$-free $3$-graphs $H$ in which every induced subhypergraph on a linearly sized vertex…

Combinatorics · Mathematics 2026-03-12 Hao Lin , Guanghui Wang , Wenling Zhou , Yiming Zhou

The binding number $b(G)$ of a graph, introduced by Woodall [J. Combin. Theory, Ser. B, 1973], is a central topic of both structural and extremal graph theory. It is closely related to fundamental combinatorial and structural properties of…

Combinatorics · Mathematics 2026-04-20 Ruifang Liu , Hongyu Chen , Ao Fan

We study Extremal Combinatorics problems where local properties are used to derive global properties. That is, we consider a given configuration where every small piece of the configuration satisfies some restriction, and use this local…

Combinatorics · Mathematics 2018-07-24 Cosmin Pohoata , Adam Sheffer