91午夜精品一区二区三区

报告题目：On the multiplicity of the least signless Laplacian eigenvalue of graphs

报告人：田凤雷

时间：2023年3月22日19:00-20:00

报告地点：线上腾讯会议（542-551-045）

数学与统计学院

2023年3月20日

报告内容：Let $G$ be a simple and connected graph of order $n(\geq 5)$. The eigenvalues of the signless Laplacian matrix $Q(G)$ of $G$ are called the $Q$-eigenvalues of $G$. Let $\rho_n(G)$ be the least $Q$-eigenvalue of $G$. In this report, we investigate the multiplicity of $\rho_n(G)$ and present all $n$-vertex graphs with $\rho_n(G)$ of multiplicity $n-3$. Moreover, it is shown that all these graphs are determined by their signless Laplacian spectra.