On graphs with some normalized Laplacian eigenvalue of extremal multiplicity

Fenglei Tian, Junqing Cai, Zuosong Liang +1

Let $G$ be a connected simple graph on $n$ vertices. Let $\mathcal{L}(G)$ be the normalized Laplacian matrix of $G$ and ${\rho }_{n-1}(G)$ be the second least eigenvalue of $\mathcal{L}(…