signed graph;
Laplacian;
second largest eigenvalue;
spectral determination;
friendship graph;
05C50;
05C22;
D O I:
10.1080/03081087.2015.1120701
中图分类号:
O1 [数学];
学科分类号:
0701 ;
070101 ;
摘要:
Let be a signed graph, where G is the underlying graph and <inline-graphic is the signature function on the edges of G. In this paper, we consider the Laplacian eigenvalues of signed graphs and we characterize the connected signed graphs whose second largest Laplacian eigenvalue does not exceed 3. Furthermore, we study the Laplacian spectral determination of most graphs in the latter family.