2025/04/22 by Zhen, Wenhao, Wong, Dein, Xu, Songnian · 1 citation
#Combinatorics (math.CO) #FOS: Mathematics
paper · doi:10.48550/arxiv.2504.15772
Let G be a connected graph on n vertices with girth g. Let mGI denote the number of Laplacian eigenvalues of graph G in an interval I. In this paper, we show that if G is not a cycle, then mG(n-g+3,n]≤ n-g. Moreover, we prove that mG(n-g+3,n]= n-g if and only if G≅ C3 or G≅ K3,2 or G≅ U1, where U1 is obtained from a cycle by joining a single vertex with a vertex of this cycle.