关于线图第二大根的极限点

On Limit Points of Second Largest Eigenvalue of Line Graphs

设Gn 为线图 ,λ2 (Gn)为Gn 的第二大根 ,给出λ2 (Gn)的最小极限点 :5 - 12 .这时 ,Gn K1r+ 1(K1r+ 1是由完全图Kr+ 1在其一顶点处与P2 的连接图 ) .

Let G n be a line graph and λ 2(G n) be the second largest eigenvalue of G n, the smallest limit point of λ 2(G n) is presented5-12. Here G nK 1 r+1( K 1 r+1 is the graph obtained by coalescence ofa complete graph K r+1 of r+1 vertices with a path P 2 of length one at one of its vertices).