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Related papers: Relative Tur\'an densities of ordered graphs

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We introduce a quantitative method to compare arbitrary pairs of graph centrality measures, based on the ordering of vertices induced by them. The proposed method is conceptually simple, mathematically elegant, and allows for a quantitative…

Social and Information Networks · Computer Science 2026-01-26 G. Exarchakos , R. van der Hofstad , O. Nagy , M. Pandey

An ordered hypergraph is a hypergraph $G$ whose vertex set $V(G)$ is linearly ordered. We find the Tur\'an numbers for the $r$-uniform $s$-vertex tight path $P^{(r)}_s$ (with vertices in the natural order) exactly when $r\le s < 2r$ and $n$…

Combinatorics · Mathematics 2022-12-29 John P. Bright , Kevin G. Milans , Jackson Porter

In this paper, we consider the Johnson's graphs. We study the extremal properties of the Johnson's graphs. Namely, we investigate the number of edges in an arbitrary subgraph of this graph. Namely, in this article we prove analogs of…

Combinatorics · Mathematics 2021-06-07 Nikita Dubinin Andreevich

Given a family ${\cal F}$ of graphs, and a positive integer $n$, the Tur\'an number $ex(n,{\cal F})$ of ${\cal F}$ is the maximum number of edges in an $n$-vertex graph that does not contain any member of ${\cal F}$ as a subgraph. The order…

Combinatorics · Mathematics 2015-02-12 Tao Jiang , Andrew Newman

This paper investigates the addition of random edges to arbitrary dense graphs; in particular, we determine the number of random edges required to ensure various monotone properties including the appearance of a fixed size clique, small…

Combinatorics · Mathematics 2016-05-25 Tom Bohman , Alan Frieze , Michael Krivelevich , Ryan R. Martin

P. Erd\H{o}s [On extremal problems of graphs and generalized graphs, Israel Journal of Mathematics 2 (1964), 183-190] characterised those hypergraphs $F$ that have to appear in any sufficiently large hypergraph $H$ of positive density. We…

Combinatorics · Mathematics 2019-01-30 Christian Reiher , Vojtěch Rödl , Mathias Schacht

In this paper, we provide a new proof of a density version of Tur\'an's theorem. We also rephrase both the theorem and the proof using entropy. With the entropic formulation, we show that some naturally defined entropic quantity is closely…

Combinatorics · Mathematics 2026-01-13 Ting-Wei Chao , Hung-Hsun Hans Yu

The class of closed graphs by a linear ordering on their sets of vertices is investigated. A recent characterization of such a class of graphs is analyzed by using tools from the proper interval graph theory.

Combinatorics · Mathematics 2015-09-23 Marilena Crupi

Recently, Bennett et al. introduced the vertex-induced weighted Tur\'an problem. In this paper, we consider their open Tur\'an problem under sum-edge-weight function and characterize the extremal structure of $K_{l}$-free graphs. Based on…

Combinatorics · Mathematics 2019-02-26 Zixiang Xu , Yifan Jing , Gennian Ge

Turan's theorem implies that every graph of order n with more edges than the r-partite Turan graph contains a complete graph of order r+1. We show that the same premise implies the existence of much larger graphs. We also prove…

Combinatorics · Mathematics 2007-11-22 Vladimir Nikiforov

We study extensions of Tur\'an Theorem in edge-weighted settings. A particular case of interest is when constraints on the weight of an edge come from the order of the largest clique containing it. These problems are motivated by…

Combinatorics · Mathematics 2026-02-17 József Balogh , Domagoj Bradač , Bernard Lidický

An ordered graph $H$ is a simple graph with a linear order on its vertex set. The corresponding Tur\'an problem, first studied by Pach and Tardos, asks for the maximum number $\text{ex}_<(n,H)$ of edges in an ordered graph on $n$ vertices…

Combinatorics · Mathematics 2017-11-22 Dániel Korándi , Gábor Tardos , István Tomon , Craig Weidert

We show that for every integer $k\geq3$, the set of Tur\'an densities of $k$-uniform hypergraphs has an accumulation point in $[0,1)$. In particular, $1/2$ is an accumulation point for the set of Tur\'an densities of $3$-uniform…

Combinatorics · Mathematics 2024-05-15 David Conlon , Bjarne Schülke

A broader definition of generalized truncations of graphs is introduced followed by an exploration of some standard concepts and parameters with regard to generalized truncations.

Combinatorics · Mathematics 2020-07-10 Brian Alspach , Joshua B. Connor

The emerging theory of graph limits exhibits an analytic perspective on graphs, showing that many important concepts and tools in graph theory and its applications can be described more naturally (and sometimes proved more easily) in…

Combinatorics · Mathematics 2023-08-01 Omri Ben-Eliezer , Eldar Fischer , Amit Levi , Yuichi Yoshida

Let $H$ be a graph on $n$ vertices and let the blow-up graph $G[H]$ be defined as follows. We replace each vertex $v_i$ of $H$ by a cluster $A_i$ and connect some pairs of vertices of $A_i$ and $A_j$ if $(v_i,v_j)$ was an edge of the graph…

Combinatorics · Mathematics 2014-07-31 Péter Csikvári , Zoltán Lóránt Nagy

In this paper, we investigate the Tur\'an exponent for $1$-subdivisions of graphs that are neither bipartite nor complete. Specifically, we establish an upper bound on the Tur\'an number of the 1-subdivision of $K_{s,t}^+$, where…

Combinatorics · Mathematics 2025-06-11 Xiao-Chuan Liu , Danni Peng , Xu Yang

Unlike graphs, determining Tur\'{a}n densities of hypergraphs is known to be notoriously hard in general. The essential reason is that for many classical families of $r$-uniform hypergraphs $\mathcal{F}$, there are perhaps many…

Combinatorics · Mathematics 2023-12-03 Jianfeng Hou , Heng Li , Guanghui Wang , Yixiao Zhang

The Tur\'an density $\pi(\cal F)$ of a family $\cal F$ of $r$-graphs is the limit as $n\to\infty$ of the maximum edge density of an $\cal F$-free $r$-graph on $n$ vertices. Erdos [Israel J. Math 2 (1964) 183--190] proved that no Tur\'an…

Combinatorics · Mathematics 2015-04-06 Oleg Pikhurko

Over recent years there has been much interest in both Tur\'an and Ramsey properties of vertex ordered graphs. In this paper we initiate the study of embedding spanning structures into vertex ordered graphs. In particular, we introduce a…

Combinatorics · Mathematics 2022-02-17 Jozsef Balogh , Lina Li , Andrew Treglown