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Given a graph $H$ and an integer $p$, the {\it edge blow-up} of $H$, denoted as $H^{p+1}$, is the graph obtained from replacing each edge in $H$ by a clique of size $p+1$ where the new vertices of the cliques are all different. The…

Combinatorics · Mathematics 2021-02-10 Long-Tu Yuan

The odd-ballooning of a graph $G$, denoted by $G_q$, is the graph obtained from replacing each edge in $G$ by a odd cycle of the same size where the new vertices of the odd cycles are all different. In 2002, Erd\"os et al. determined the…

Combinatorics · Mathematics 2023-06-19 Tao Fang , Xiying Yuan

The edge blow-up of a graph $G$, denoted by $G^{p+1}$, is obtained by replacing each edge of $G$ with a clique of order $p+1$, where the new vertices of the cliques are all distinct. Yuan [J. Comb. Theory, Ser. B, 152 (2022) 379-398]…

Combinatorics · Mathematics 2023-06-30 Jing Wang , Zhenyu Ni , Liying Kang , Yi-zheng Fan

Given a graph $H$ and an integer $p$ ($p\geq 2$), the edge blow-up $H^{p+1}$ of $H$ is the graph obtained from replacing each edge in $H$ by a clique of order $(p+1)$, where the new vertices of the cliques are all distinct. The Tur\'{a}n…

Combinatorics · Mathematics 2022-02-15 Yanni Zhai , Xiying Yuan , Zhenyu Ni

The edge blow-up of a graph $F$ is the graph obtained from replacing each edge in $F$ by a clique of the same size where the new vertices of the cliques are all different. In this article, we concern about the Tur\'an problem for the edge…

Combinatorics · Mathematics 2020-08-25 Anyao Wang , Xinmin Hou , Boyuan Liu , Yue Ma

An extremal graph for a given graph $H$ is a graph with maximum number of edges on fixed number of vertices without containing a copy of $H$. The $k$-th power of a path is a graph obtained from a path and joining all pair of vertices of the…

Combinatorics · Mathematics 2020-03-31 Long-Tu Yuan

The edge blow-up of a graph is the graph obtained from replacing each edge of it by a clique of the same size where the new vertices of the cliques are all different. Wang, Hou, Liu and Ma determined the Tur\'{a}n number of the edge blow-up…

Combinatorics · Mathematics 2022-06-13 Cheng Chi , Long-Tu Yuan

An extremal graph for a graph $H$ on $n$ vertices is a graph on $n$ vertices with maximum number of edges that does not contain $H$ as a subgraph. Let $T_{n,r}$ be the Tur\'{a}n graph, which is the complete $r$-partite graph on $n$ vertices…

Combinatorics · Mathematics 2015-10-29 Xinmin Hou , Yu Qiu , Boyuan Liu

Let $H$ be a graph and $p$ be an integer. The edge blow-up $H^p$ of $H$ is the graph obtained from replacing each edge in $H$ by a copy of $K_p$ where the new vertices of the cliques are all distinct. Let $C_k$ and $P_k$ denote the cycle…

Combinatorics · Mathematics 2022-10-24 Zequn Lv , Ervin Győri , Zhen He , Nika Salia , Casey Tompkins , Kitti Varga , Xiutao Zhu

Cycles have many interesting properties and are widely studied in many disciplines. In some areas, maximising the counts of $k$-cycles are of particular interest. A natural candidate for the construction method used to maximise the number…

Combinatorics · Mathematics 2022-07-27 S. Y. Chan , K. Morgan , J. Ugon

An extremal graph for a given graph $H$ is a graph on $n$ vertices with maximum number of edges that does not contain $H$ as a subgraph. Let $s,t$ be integers and let $H_{s,t}$ be a graph consisting of $s$ triangles and $t$ cycles of odd…

Combinatorics · Mathematics 2016-10-05 Xinmin Hou , Yu Qiu , Boyuan Liu

A cornerstone of extremal graph theory due to Erd\H{o}s and Stone states that the edge density which guarantees a fixed graph $F$ as subgraph also asymptotically guarantees a blow-up of $F$ as subgraph. It is natural to ask whether this…

Combinatorics · Mathematics 2026-04-01 Richard Lang , Nicolás Sanhueza-Matamala

For a family $\mathcal{F}$ of graphs, let $ex(n,\mathcal{F})$ denote the maximum number of edges in an $n$-vertex graph which contains none of the members of $\mathcal{F}$ as a subgraph. A longstanding problem in extremal graph theory asks…

Combinatorics · Mathematics 2022-12-06 Jie Ma , Tianchi Yang

The Erd\H{o}s-Simonovits stability theorem is one of the most widely used theorems in extremal graph theory. We obtain an Erd\H{o}s-Simonovits type stability theorem in multi-partite graphs. Different from the Erd\H{o}s-Simonovits stability…

Combinatorics · Mathematics 2026-01-14 Wanfang Chen , Changhong Lu , Long-Tu Yuan

For a graph $H$, the Tur\'{a}n number of $H$, denoted by ex$(n,H)$, is the maximum number of edges of an $n$-vertex $H$-free graph. Let $g(n,H)$ denote the maximum number of edges not contained in any monochromatic copy of $H$ in a…

Combinatorics · Mathematics 2021-05-13 Long-Tu Yuan

Let ${\rm ex}(n,F)$ and ${\rm spex}(n,F)$ be the maximum size and maximum spectral radius of an $F$-free graph of order $n$, respectively. The value ${\rm spex}(n,F)$ is called the spectral extremal value of $F$. Nikiforov [J. Graph Theory…

Combinatorics · Mathematics 2023-12-19 Longfei Fang , Huiqiu Lin

In this paper we present a novel approach in extremal set theory which may be viewed as an asymmetric version of Katona's permutation method. We use it to find more Tur\'an numbers of hypergraphs in the Erd\H{o}s--Ko--Rado range. An…

Combinatorics · Mathematics 2020-03-03 Zoltán Füredi , Tao Jiang , Alexandr Kostochka , Dhruv Mubayi , Jacques Verstraëte

The blow-up of a graph is obtained by replacing every vertex with a finite collection of copies so that the copies of two vertices are adjacent if and only if the originals are. If every vertex is replaced with the same number of copies,…

Combinatorics · Mathematics 2011-08-30 Hamed Hatami , James Hirst , Serguei Norine

A \emph{clique} is a set of pairwise adjacent vertices in a graph. We determine the maximum number of cliques in a graph for the following graph classes: (1) graphs with $n$ vertices and $m$ edges; (2) graphs with $n$ vertices, $m$ edges,…

Combinatorics · Mathematics 2010-06-17 David R. Wood

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
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