English

The unicyclic hypergraph with extremal spectral radius

Combinatorics 2023-07-14 v2

Abstract

For a hypergraphhypergraph G=(V,E)\mathcal{G}=(V, E) consisting of a nonempty vertex set V=V(G)V=V(\mathcal{G}) and an edge set E=E(G)E=E(\mathcal{G}), its adjacencyadjacency matrixmatrix AG=[(AG)ij]\mathcal {A}_{\mathcal{G}}=[(\mathcal {A}_{\mathcal{G}})_{ij}] is defined as (AG)ij=eEij1e1(\mathcal {A}_{\mathcal{G}})_{ij}=\sum_{e\in E_{ij}}\frac{1}{|e| - 1}, where Eij={eEi,je}E_{ij} = \{e \in E \, |\, i, j \in e\}.The spectralspectral radiusradius of a hypergraph G\mathcal{G}, denoted by ρ(G)\rho(\mathcal {G}), is the maximum modulus among all eigenvalues of AG\mathcal {A}_{\mathcal{G}}. In this paper, among all kk-uniform (k3k\geq 3) unicyclic hypergraphs with fixed number of vertices, the hypergraphs with the maximum and the second the maximum spectral radius are completely determined, respectively.

Keywords

Cite

@article{arxiv.2306.16027,
  title  = {The unicyclic hypergraph with extremal spectral radius},
  author = {Guanglong Yu and Lin Sun},
  journal= {arXiv preprint arXiv:2306.16027},
  year   = {2023}
}

Comments

arXiv admin note: substantial text overlap with arXiv:2306.10184

R2 v1 2026-06-28T11:16:32.813Z