Yichen Wang

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20242026

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13 papers · 1 filter

math.CO2026

Counting $t$ -wise $L$ -intersecting cliques with prescribed intersection sizes

Yiyan Zhan, Yichen Wang, Mei Lu

Let $r, t \geq 3$ be integers and $L = {ℓ_{1}, ℓ_{2}, \dots, ℓ_{s}} \subseteq [0, r - 1]$ a fixed set of integers with $∣ L ∣ \neq = r$ and $ℓ_{1} < ℓ_{2} < \dots < ℓ_{s}$ . For each integer $n$ …

math.CO2026

Inversion Diameter of Planar Graphs

Yichen Wang, Yuxuan Yang

Given an oriented graph $G$ and a subset of vertices $X \subseteq V (G)$ , the \emph{inversion} of $X$ is the operation that reverses the orientation of every arc with bo…

math.CO2026

A stability theorem for Berge Hamiltonian cycles under a minimum degree condition

Yichen Wang, Dániel Gerbner, Xiamiao Zhao

In this paper, we study extremal and stability problems for Berge Hamiltonian cycles in $r$ -uniform hypergraphs under a minimum degree condition. Let $ g_r(n,t)=\binom{n-t}{r}+t\bi…

math.CO2026

The maximum number of odd cycles in planar graphs forbidding shorter odd cycles

Yichen Wang, Ervin Győri, Zhen He

Given a graph $H$ and a family of graphs $F$ , the generalized planar Turán number $ex_{P} (n, H, F)$ is the maximum number of copies of $H$ in a…

math.CO2026

On the Turán number of blow-ups of $F_{5}$

Xiamiao Zhao, Xin Cheng, Dániel Gerbner +4

Let $F_{5}$ denote the $3$ -uniform hypergraph on the vertex set ${f_{1}, f_{2}, \dots, f_{5}}$ with hyperedges ${f_{1} f_{2} f_{3}, f_{1} f_{2} f_{4}, f_{3} f_{4} f_{5}}$ . Recently, Balogh, Clemen and Lu…

math.CO2026

Algorithm for finding vertex-edge domination number on graphs with bounded treewidth and related problems on planar graphs

Yichen Wang, Haixiang Zhang, Mei Lu

Given a graph $G = (V, E)$ , a vertex $u \in V$ {\em ve-dominates} all edges incident to any vertex of $N_{G} [u]$ . A set $S \subseteq V$ is a {\em ve-dominating set} if for all edges $e\…

math.CO2026

A generalization of Erdős-Hajnal problem on paths with equal-degree endpoints

Xiamiao Zhao, Yichen Wang, Mei Lu

Erdős and Hajnal proposed a problem that: is it true that every $(2 n + 1)$ -vertex graph with $n^{2} + n + 1$ edges contains two vertices of equal degree connected by a path of length three…

math.CO2026

On the largest chromatic number of $F$ -free hypergraphs

Yichen Wang, Mengyu Duan, Dániel Gerbner +1

Given a hypergraph $F$ , what is the largest chromatic number that an $F$ -free hypergraph can have? In the case of graphs, this question is easy to answer: the chromatic number is u…

math.CO2026

The number of induced paths in outerplanar graphs

Yichen Wang, Ervin Győri, Casey Tompkins +1

Let $P_{k}$ denote the path with $k$ vertices, and $ex_{O P} (n, H^{ind}, \emptyset)$ be the maximum number of induced copies of $H$ in an $n$ -vertex outerpla…

math.CO2026

Forbidding matching as trace in uniform hypergraphs

Yichen Wang, Xin Cheng, Ervin Győri +1

We say a hypergraph $H$ contains a hypergraph $G$ as trace if there exists a vertex subset $S \subseteq V (H)$ such that $∣ S ∣ = ∣ V (G) ∣$ and $…

math.CO2026

The Turán number of the Cartesian product of a star and an edge

Xiamiao Zhao, Xin Cheng, Cheng Chi +3

Let $C_{k}$ denote the cycle of length $k$ , $S_{t}$ be a star with $t$ edges. And let $B_{t}$ be the graph consisting of $t$ copies of $C_{4}$ sharing one fixed edge. Equivalently, $B_t=K_…

math.CO2026

Forbidding edge-critical graphs as trace in uniform hypergraphs

Yichen Wang, Xin Cheng, Ervin Győri +3

We say a hypergraph $H$ contains a graph $G$ as trace if there exists a vertex subset $S \subseteq V (H)$ such that $∣ S ∣ = V (G)$ and $\{e \cap S \mid e \in E(\ma…

math.CO2026

The maximum number of triangles in graphs without the square of a path

Yichen Wang, Ervin Győri

The generalized Turán number for $H$ of $G$ , denoted by $\ex(n,H,G)$, is the maximum number of copies of $H$ in an $n$ -vertex $G$ -free graph. When $H$ is an edge, $\ex(n,H,G)$ is t…

Counting t-wise L-intersecting cliques with prescribed intersection sizes

Inversion Diameter of Planar Graphs

A stability theorem for Berge Hamiltonian cycles under a minimum degree condition

The maximum number of odd cycles in planar graphs forbidding shorter odd cycles

On the Turán number of blow-ups of F5​

Algorithm for finding vertex-edge domination number on graphs with bounded treewidth and related problems on planar graphs

A generalization of Erdős-Hajnal problem on paths with equal-degree endpoints

On the largest chromatic number of F-free hypergraphs

The number of induced paths in outerplanar graphs

Forbidding matching as trace in uniform hypergraphs

The Turán number of the Cartesian product of a star and an edge

Forbidding edge-critical graphs as trace in uniform hypergraphs

The maximum number of triangles in graphs without the square of a path

Counting $t$ -wise $L$ -intersecting cliques with prescribed intersection sizes

On the Turán number of blow-ups of $F_{5}$

On the largest chromatic number of $F$ -free hypergraphs