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Let $F$ be a graph of order $r$. In this paper, we study the maximum number of induced copies of $F$ with restricted intersections, which highlights the motivation from extremal set theory. Let $L=\{\ell_1,\dots,\ell_s\}\subseteq[0,r-1]$ be…

Combinatorics · Mathematics 2025-09-22 Haixiang Zhang , Yichen Wang , Xiamiao Zhao , Mei Lu

For fixed graphs $F$ and $H$, the generalized Tur\'an problem asks for the maximum number $ex(n,H,F)$ of copies of $H$ that an $n$-vertex $F$-free graph can have. In this paper, we focus on cases with $F$ being $B_{r,s}$, the graph…

Combinatorics · Mathematics 2022-02-08 Dániel Gerbner , Balázs Patkós

In this work, we give the sharp upper bound for the number of cliques in graphs with bounded odd circumferences. This generalized Tur\'an-type result is an extension of the celebrated Erd\H{o}s and Gallai theorem and a strengthening of…

Combinatorics · Mathematics 2022-12-07 Zequn Lv , Ervin Győri , Zhen He , Nika Salia , Chuanqi Xiao , Xiutao Zhu

For an integer $r \ge 3$ and a subset $L \subset [0,r-1]$, a graph $G$ is $(K_{r}, L)$-intersecting if the number of vertices in the intersection of every pair of $K_r$ in $G$ belongs to $L$. We study the maximum number of $K_r$ in an…

Combinatorics · Mathematics 2024-04-04 Charlotte Helliar , Xizhi Liu

Tur\'{a}n's theorem is a cornerstone of extremal graph theory. It asserts that for any integer $r \geq 2$ every graph on $n$ vertices with more than ${\tfrac{r-2}{2(r-1)}\cdot n^2}$ edges contains a clique of size $r$, i.e., $r$ mutually…

Combinatorics · Mathematics 2016-10-25 Christian Reiher

Generalized Tur\'an problems have been a central topic of study in extremal combinatorics throughout the last few decades. One such problem is maximizing the number of cliques of size $t$ in a graph of a fixed order that does not contain…

Combinatorics · Mathematics 2024-03-01 Debsoumya Chakraborti , Da Qi Chen

Let $\mathcal{H}$ be a family of graphs. The generalized Tur\'an number $ex(n, K_r, \mathcal{H})$ is the maximum number of copies of the clique $K_r$ in any $n$-vertex $\mathcal{H}$-free graph. In this paper, we determine the value of…

Combinatorics · Mathematics 2024-09-17 Xiaona Fang , Xiutao Zhu , Yaojun Chen

The fundamental theorem of Tur\'{a}n from Extremal Graph Theory determines the exact bound on the number of edges $t_r(n)$ in an $n$-vertex graph that does not contain a clique of size $r+1$. We establish an interesting link between…

Data Structures and Algorithms · Computer Science 2023-07-17 Fedor V. Fomin , Petr A. Golovach , Danil Sagunov , Kirill Simonov

Let $\cal H$ be a family of graphs. The Tur\'an number ${\rm ex}(n,{\cal H})$ is the maximum possible number of edges in an $n$-vertex graph which does not contain any member of $\cal H$ as a subgraph. As a common generalization of…

Combinatorics · Mathematics 2024-12-13 Chunyang Dou , Bo Ning , Xing Peng

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

Let $P \subset \mathbb{R}^{2}$ be a Katz-Tao $(\delta,s)$-set, and let $\mathcal{L}$ be a Katz-Tao $(\delta,t)$-set of lines in $\mathbb{R}^{2}$. A recent result of Fu and Ren gives a sharp upper bound for the $\delta$-covering number of…

Combinatorics · Mathematics 2024-02-20 Tuomas Orponen , Guangzeng Yi

The problem of maximising the number of cliques among $n$-vertex graphs from various graph classes has received considerable attention. We investigate this problem for the class of $1$-planar graphs where we determine precisely the maximum…

Combinatorics · Mathematics 2021-09-08 J. Pascal Gollin , Kevin Hendrey , Abhishek Methuku , Casey Tompkins , Xin Zhang

We give a Hilton-Milner Theorem for the $r$-independent sets in the graph that is the union of copies of $K_k$. That is, we determine the maximum intersecting families of $r$-independent sets in this graph, subject to the condition that the…

Combinatorics · Mathematics 2025-11-25 Karen Gunderson , Karen Meagher , Joy Morris , Venkata Raghu Tej Pantangi

Fix integers $n \ge r \ge 2$. A clique partition of ${[n] \choose r}$ is a collection of proper subsets $A_1, A_2, ..., A_t \subset [n]$ such that $\bigcup_i{A_i \choose r}$ is a partition of ${[n] \choose r}$. Clique partitions are related…

Combinatorics · Mathematics 2010-06-29 Keith Mellinger , Dhruv Mubayi , Jacques Verstraete

We study the maximum number of $r$-vertex cliques in $(r-1)$-uniform hypergraphs not containing complete $r$-partite hypergraphs $K_r^{(r-1)}(a_1, \dots, a_r)$. By using the hypergraph removal lemma, we show that this maximum is $o( n^{r -…

Combinatorics · Mathematics 2025-06-12 Ayush Basu , Vojtech Rodl , Yi Zhao

We investigate lower bounds on the average degree in r-cliques in graphs of order n and size greater than t(r,n), where t(r,n) is the size of the Turan graph on n vertices and r color classes. Continuing earlier research of Edwards and…

Combinatorics · Mathematics 2007-05-23 B. Bollobas , V. Nikiforov

We estimate the maximum possible number of cliques of size $r$ in an $n$-vertex graph free of a fixed complete $r$-partite graph $K_{s_1, s_2, \ldots, s_r}$. By viewing every $r$-clique as a hyperedge, the upper bound on the Tur\'an number…

Combinatorics · Mathematics 2025-03-25 József Balogh , Suyun Jiang , Haoran Luo

In this paper we continue the study of a natural generalization of Tur\'an's forbidden subgraph problem and the Ruzsa-Szemer\'edi problem. Let $ex_F(n,G)$ denote the maximum number of edge-disjoint copies of a fixed simple graph $F$ that…

Combinatorics · Mathematics 2024-04-02 Benedek Kovács , Zoltán Lóránt Nagy

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

We consider the problem of finding a large clique in an Erd\H{o}s--R\'enyi random graph where we are allowed unbounded computational time but can only query a limited number of edges. Recall that the largest clique in $G \sim G(n,1/2)$ has…

Combinatorics · Mathematics 2024-07-12 Endre Csóka , András Pongrácz
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