Operations Research Transactions ›› 2015, Vol. 19 ›› Issue (2): 99-104.doi: 10.15960/j.cnki.issn.1007-6093.2015.02.011

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The maximum signless Laplacian separator of unicyclic and bicyclic graphs

JIAN Xiangguo1,YUAN Xiying1,*,ZHANG Man1   

  1. 1. Department of Mathematics, College of Sciences,Shanghai University, Shanghai 200444, China
  • Received:2014-10-02 Online:2015-06-15 Published:2015-06-15

Abstract:

Let G be a graph of order n and q_{1}(G)\geq q_{2}(G)\geq \cdots \geq q_{n}(G) be its Q-eigenvalues. The signless Laplacian separator  S_{Q}(G) of G is defined as S_{Q}(G)=q_{1}(G)-q_{2}(G). In this paper, we study the maximum signless Laplacian separator of unicyclic and bicyclic graphs and characterize the extremal graphs, respectively.

Key words: unicyclic graph, bicyclic graph, signless Laplacian separator, signless Laplacian matrix