介绍了一类直径为4的n阶树即双星图T(a,b)的谱随a变化的规律,其中a≥b≥1,a+b+3=n,n 2-3≤a≤n-4;得到了双星图T(a,b)的邻接谱半径、Laplace谱半径以及代数连通度均随a的值递增的结论,并在此基础上对这类树进行了排序。
The problem of ordring one kind of trees with diameter 4 which denoted as T(a,b) is introduced,where a≥b≥1,a+b+3=n,≤a≤n-4.The spectral radius and the Laplacian radius of T(a,b) are obatined.It deduced that the adjacent spectrum and Laplacian spectrum are strictly increasing functions of a respectively,the spectrum ordering is also produced.