Wenqian Zhang

collaborators

3 papers

math.CO2026

The toughness of random graphs

Guang Li, Wenqian Zhang

For a connected and non-complete graph $G$ of order $n$ , its toughness is defined as \[ τ(G)=\min\bigl\{|S|/c(G-S):S\subseteq V(G),\ c(G-S)>1\bigr\}, \] where $c (G - S)$ denotes the…

math.CO2026

Extremal graphs for disjoint union of stars and paths

Wenqian Zhang

Let $F$ be a graph. A graph $G$ is called $F$ -free if $G$ does not contain $F$ as a subgraph. Let $EX (n, F)$ denote the set of $F$ -free graphs of order $n$ with the maximum ed…

math.CO2021

A best bound for $λ_{2} (G)$ to guarantee $κ (G) \geq 2$

Wenqian Zhang, Jianfeng Wang

Let $G$ be a connected $d$ -regular graph with a given order and the second largest eigenvalue $λ_{2} (G)$ . Mohar and O (private communication) asked a challenging problem: what is the…

The toughness of random graphs

Extremal graphs for disjoint union of stars and paths

A best bound for λ2​(G) to guarantee κ(G)≥2

A best bound for $λ_{2} (G)$ to guarantee $κ (G) \geq 2$