图的Laplace spread定义为图的最大Laplace特征值与次小Laplace特征值之差.利用多项式函数的性质,得到了具有最大Laplace spread的双圈图.
The Laplacian spread of a graph is defined to be the difference between the largest and the second-smallest Laplacian eigenvalues of the graph. Using properties of polynomial, we characterized the graphs with the maximal Laplacian spread among all bicyclic graphs.