Order ( IF 0.4 ) Pub Date : 2021-05-08 , DOI: 10.1007/s11083-021-09566-3 Dragan Stevanović
The k-th spectral moment Mk(G) of the adjacency matrix of a graph G represents the number of closed walks of length k in G. We study here the partial order ≼ of graphs, defined by G ≼ H if Mk(G) ≤ Mk(H) for all k ≥ 0, and are interested in the question when is ≼ a linear order within a specified set of graphs? Our main result is that ≼ is a linear order on each set of starlike trees with constant number of vertices. Recall that a connected graph G is a starlike tree if it has a vertex u such that the components of G − u are paths, called the branches of G. It turns out that the ≼ ordering of starlike trees with constant number of vertices coincides with the shortlex order of sorted sequence of their branch lengths.
中文翻译:
通过光谱矩的总和对星形树进行排序
的ķ个频谱力矩中号ķ(ģ的曲线图的邻接矩阵的)ģ代表长度的封闭的阶层的数量ķ在ģ。在这里,我们研究图的偏序≼,由下式定义ģ ≼ ħ如果中号ķ(ģ)≤中号ķ(ħ)的所有ķ时是≼指定的一组内的线性顺序≥0,和感兴趣的问题图?我们的主要结果是,≼是每组具有恒定顶点数的星形树的线性阶数。回想一下连通图G如果它的顶点u使得G − u的分量是路径,则称为星形树,称为G的分支。事实证明,具有恒定顶点数的星形树的≼顺序与其分支长度的排序序列的shortlex顺序重合。