As tree is an easy and special graph, the study of its eigenvalue can help understand some algebra nature of spectrum.
树作为一类简单而特殊的图，对它的特征值的研究能帮助了解谱的一些代数性质。
2
The path spectrumof a graph g, denoted by ps (g), is the set of length of all maximal paths in the graph.
如果图中的一条路不是其他任何路的子路，则称这条路为该图的一条极大路。
3
The software, which has over forty functions, is described. Two functions, the overlap peak of infrared spectrum and spectrum graph print, are discussed in detail.