On the Signless Laplacian Spectral Radius of C4-free k-cyclic Graphs  

作　　者：KONG Qi WANG Li-gong 

机构地区：[1]Departmant of Applied Mathematics, School of Science, Northwestern Polytechnical University,Xi'an 710072, China

出　　处：《Chinese Quarterly Journal of Mathematics》2017年第3期238-245,共8页数学季刊（英文版）

基　　金：Supported by the National Natural Science Foundation of China（11171273）; Supported by the Seed Foundation of Innovation and Creation for Graduate Students in Northwestern Polytechnical Uni- versity（Z2016170）

摘　　要：A k-cyclic graph is a connected graph of order n and size n + k-1. In this paper, we determine the maximal signless Laplacian spectral radius and the corresponding extremal graph among all C_4-free k-cyclic graphs of order n. Furthermore, we determine the first three unicycles and bicyclic, C_4-free graphs whose spectral radius of the signless Laplacian is maximal. Similar results are obtained for the(combinatorial)A k-cyclic graph is a connected graph of order n and size n ＋ k - 1. In this paper, we determine the maximal signless Laplacian spectral radius and the corresponding extremal graph among all C4-free k-cyclic graphs of order n. Furthermore, we determine the first three unicycles and bicyclic, C4-free graphs whose spectral radius of the signless Laplacian is maximal. Similar results are obtained for the（combinatorial） Laplacian.

关 键 词：k-cyclic graph C4-free signless Laplacian spectral radius Laplacian spectral radius 

分 类 号：O157.5[理学—数学]