activity
20242026
collaborators

8 papers

math.SP2026

Graphs with maximal Laplacian eigenvalue multiplicity

Songnian Xu, Xiaoya Li, Dein Wong +1

In this paper, \( G \) is a simple connected graph, and \( m_G(λ) \) denotes the multiplicity of \( λ\) as an eigenvalue of the Laplacian matrix \( L(G) \). Let \( p(G) \) denote…

math.SP2026

The multiplicity of the laplacian eigenvalue 1 of a tree

Songnian Xu, Dein Wong, Wenhao Zhen

Let be a connected, undirected simple graph. Denote by the Laplacian matrix of , and let be the multiplicity of an eigenvalue of . When is…

math.GR2025

-partite oriented semiregular representation of valency 3 for finite groups

Songnian Xu, Dein Wong, Wenhao Zhen

Let be a finite group and a positive integer. We say that admits an \emph{oriented -semiregular representation} (abbreviated as OmSR) if there exists a -Ca…

math.GR2025

The -partite digraphical representations of valency 3 of finite groups generated by two elements

Songnian Xu, Dein Wong, Chi Zhang +1

Let be a finite group and be an integer. We employ the notation to represent elements in the Cartesian product , where d…

math.CO2025

Laplacian eigenvalue distribution and girth of graphs

Wenhao Zhen, Dein Wong, Songnian Xu

Let be a connected graph on vertices with girth . Let denote the number of Laplacian eigenvalues of graph in an interval . In this paper, we show that if $…

math.SP2024

Line graphs with the largest eigenvalue multiplicity

Wenhao Zhen, Dein Wong, Songnian Xu

For a connected graph , we denote by , , and the line graph of , the eigenvalue multiplicity of in , the cyclomatic number and the numb…