Hangxi Cha

collaborators

4 papers

math.CO2026

Asymptotic spectral radius of nonregular graphs

Hangxi Cha, Haiying Shan

Let $λ_{1} (n, Δ)$ be the maximum adjacency spectral radius among connected nonregular simple graphs of order $n$ and maximum degree $Δ$ . Using effective resistance bounds, explicit co…

math.CO2026

Uniform Hypergraphs with $α$ -Spectral Radius at Most That of a Loose Cycle

Hangxi Cha, Xiaoqi Liu, Haiying Shan

Let $k \geq 3$ and $α \in [0, 1)$ , and let $λ_{k} (α)$ denote the $α$ -spectral radius of a $k$ -uniform loose cycle. Lu and Man classified all connected $k$ -uniform hypergraphs with adjace…

math.CO2026

Graphs with zero as a main eigenvalue of the signless Laplacian

Hangxi Cha, Haiying Shan

An eigenvalue of the signless Laplacian $Q (G)$ is $Q$ -main if its eigenspace is not orthogonal to the all-ones vector. We characterize graphs with exactly $ℓ \geq 3$ $Q$ -main eigen…

math.CO2026

Trees with exactly three main eigenvalues

Hangxi Cha, Haiying Shan

An eigenvalue of a graph is called main if its eigenspace is not orthogonal to the all-ones vector. Introduced by Cvetković in the early 1970s and systematically studied by Rowlins…

Asymptotic spectral radius of nonregular graphs

Uniform Hypergraphs with α-Spectral Radius at Most That of a Loose Cycle

Graphs with zero as a main eigenvalue of the signless Laplacian

Trees with exactly three main eigenvalues

Uniform Hypergraphs with $α$ -Spectral Radius at Most That of a Loose Cycle