English

On mixed graphs whose Hermitian spectral radii are at most 2

Combinatorics 2019-10-09 v1

Abstract

A mixed graph is a graph with undirected and directed edges. Guo and Mohar in 2017 determined all mixed graphs whose Hermitian spectral radii are less than 22. In this paper, we give a sufficient condition which can make Hermitian spectral radius of a connected mixed graph strictly decreasing when an edge or a vertex is deleted, and characterize all mixed graphs with Hermitian spectral radii at most 22 and with no cycle of length 44 in their underlying graphs.

Keywords

Cite

@article{arxiv.1910.03167,
  title  = {On mixed graphs whose Hermitian spectral radii are at most 2},
  author = {Bo-Jun Yuan and Yi Wang and Shi-Cai Gong and Yun Qiao},
  journal= {arXiv preprint arXiv:1910.03167},
  year   = {2019}
}
R2 v1 2026-06-23T11:37:09.876Z