运筹学学报 ›› 2024, Vol. 28 ›› Issue (1): 112-120.doi: 10.15960/j.cnki.issn.1007-6093.2024.01.009

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链图的距离特征值

吕雪征1, 马梦郁1,*()   

  1. 1. 中国人民大学数学学院, 北京 100872
  • 收稿日期:2020-12-25 出版日期:2024-03-15 发布日期:2024-03-15
  • 通讯作者: 马梦郁 E-mail:senorita@ruc.edu.cn
  • 基金资助:
    国家自然科学基金(11971479)

The distance spectra of chain graphs

Xuezheng LYU1, Mengyu MA1,*()   

  1. 1. School of Mathematics, Renmin University of China, Beijing 100872, China
  • Received:2020-12-25 Online:2024-03-15 Published:2024-03-15
  • Contact: Mengyu MA E-mail:senorita@ruc.edu.cn

摘要:

如果一个图G不包含2K2, C3C5作为导出子图, 称其为链图。在所有点数和边数给定的连通二部图中, 链图具有最大的谱半径, 这使得链图在图谱理论中占有一席之地。本文研究了连通链图距离特征值的分布情况。对于点数为n的连通链图G=G(t1, …, th; s1, …, sh), 我们证明了-2是G的重数为n-2h的距离特征值, 且Gh-1个距离特征值小于-2和h+1个距离特征值大于-2。

关键词: 链图, 距离特征值, 合理划分

Abstract:

A graph is called a chain graph if it does not contain induced $2K_2$, $C_3$ or $C_5$. In spectral graph theory, chain graphs feature as graphs whose largest eigenvalue within the connected bipartite graphs of fixed order and size is maximal. In this paper, we consider the distance eigenvalues of a connected chain graph $G$. We present that $-2$ is an eigenvalue of $G=G(t_1,\cdots,t_h; s_1,\cdots,s_h)$, with multiplicity $n-2h$. And further more, there are exactly $h-1$ eigenvalues less than -2 and exactly $h+1$ eigenvalues greater than -2.

Key words: chain graphs, distance spectrum, equitable partition

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