Operations Research Transactions ›› 2024, Vol. 28 ›› Issue (1): 112-120.doi: 10.15960/j.cnki.issn.1007-6093.2024.01.009

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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

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

CLC Number: