关于图的第二大根的极限点

On Limit Points of Second Largest Eigenvalue of Graphs

设 G 为无孤立点的简单图,λ2( G) 为 G 的第二大特征根。该文给出区间13 , 33 - 52 内的所有第二大根的极限点- (5k - 1) + 33k2 + 14k + 12(k + 3) ( 其中k ∈N) 。因而3 - 12 , 161 - 910 , 85 - 76 分别为L2 中的第二,三,四个最小值,其中Lt = ｛r｜ r 为图的第t 个大根的极限点｝ 。

Let G be a simple graph without isolated point. We denote λ 2 (G) the second largest eignvalue of G . In this paper, all limit points of λ 2 (G) belonged to 13, 33-52 are presented: -(5k-1)+33k 2+14k+12(k+3) (k∈N) . Thus 3-12,161-910,85-76 are the second, third, forth least value of L 2 , respectively, where L t={r｜r is the t th largest eigenvalue limit points of graphs}.