The spread of unicyclic graphs with given size of maximum matchings

被引:17
作者
Li, Xueliang [1 ]
Zhang, Jianbin
Zhou, Bo
机构
[1] Nankai Univ, Ctr Cominator, Tianjin 300071, Peoples R China
[2] Nankai Univ, LPMC, Tianjin 300071, Peoples R China
[3] S China Normal Univ, Dept Math, Guangzhou 510631, Peoples R China
关键词
spread; unicyclic graph; characteristic polynomial; eigenvalue;
D O I
10.1007/s10910-006-9141-6
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
The spread s(G) of a graph G is defined as s(G) = max (i,j) |lambda (i) -lambda (j)|, where the maximum is taken over all pairs of eigenvalues of G. Let U(n,k) denote the set of all unicyclic graphs on n vertices with a maximum matching of cardinality k, and U*(n,k) the set of triangle-free graphs in U(n,k). In this paper, we determine the graphs with the largest and second largest spectral radius in U*(n,k), and the graph with the largest spread in U(n,k).
引用
收藏
页码:775 / 788
页数:14
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