Yichen Wang

activity

20242026

collaborators

20 papers

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…

math.CO2025

Edge version of the inducibility via the entropy method

Yichen Wang, Xiamiao Zhao, Mei Lu

The inducibility of a graph $H$ is about the maximum number of induced copies of $H$ in a graph on $n$ vertices. We consider its edge version, that is, the maximum number of induce…

math.CO2025

The Turán number of Berge matchings

Yichen Wang, Zixuan Yang, Xiamiao Zhao +2

Given a graph $F$ , an $r$ -uniform hypergraph $H$ is a {\em Berge- $F$ } if there is a bijection $ϕ : E (F) \to E (H)$ such that $e \subseteq ϕ (e)$ for each $e \in E (F)$ .…

math.CO2025

Counting induced subgraphs with given intersection sizes

Haixiang Zhang, Yichen Wang, Xiamiao Zhao +1

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 se…

math.CO2025

Linear recoloring diameter of degenerate chordal graphs and bounded treewidth graphs

Yichen Wang, Mei Lu

Let $G$ be a graph on $n$ vertices and $t$ an integer. The reconfiguration graph of $G$ , denoted by $R_{t} (G)$ , consists of all $t$ -colorings of $G$ and two $t$ -colorings are adjacen…

math.CO2024

Inversion diameter and treewidth

Yichen Wang, Haozhe Wang, Yuxuan Yang +1

In an oriented graph $G$ , the inversion of a subset $X$ of vertices is the operation that reverses the orientation of all arcs with both end-vertices in $X$ . The i…

math.CO2024

Treewidth of generalized Hamming graph, bipartite Kneser graph and generalized Petersen graph

Yichen Wang, Mengyu Cao, Zequn Lv +1

Let $t, q$ and $n$ be positive integers. Write $[q] = {1, 2, \dots, q}$ . The generalized Hamming graph $H (t, q, n)$ is the graph whose vertex set is the cartesian product of $n$ copie…

math.CO2024

A polynomial time algorithm to find star chromatic index on bounded treewidth graphs with given maximum degree

Yichen Wang, Mei Lu

A star edge coloring of a graph $G$ is a proper edge coloring with no 2-colored path or cycle of length four. The star edge coloring problem is to find an edge coloring of a given…

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

Edge version of the inducibility via the entropy method

The Turán number of Berge matchings

Counting induced subgraphs with given intersection sizes

Linear recoloring diameter of degenerate chordal graphs and bounded treewidth graphs

Inversion diameter and treewidth

Treewidth of generalized Hamming graph, bipartite Kneser graph and generalized Petersen graph

A polynomial time algorithm to find star chromatic index on bounded treewidth graphs with given maximum degree

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