English

The $A_\alpha$ spectral radius with given independence number $n-4$

Combinatorics 2022-11-01 v1

Abstract

Let GG be a graph with adjacency matrix A(G)A(G) and degree diagonal matrix D(G)D (G). In 2017, Nikiforov [Appl. Anal. Discrete Math., 11 (2017) 81--107] defined the matrix Aα(G)=αD(G)+(1α)A(G)A_\alpha(G) = \alpha D(G) + (1-\alpha)A(G) for any real α[0,1]\alpha\in[0,1]. The largest eigenvalue of A(G)A(G) is called the spectral radius of GG, while the largest eigenvalue of Aα(G)A_\alpha(G) is called the AαA_\alpha spectral radius of GG. Let Gn,i\mathcal{G}_{n,i} be the set of graphs of order nn with independence number ii. Recently, for all graphs in Gn,i\mathcal{G}_{n,i} having the minimum or the maximum AA, QQ and AαA_\alpha spectral radius where i{1,2,n2n2+1,n3,n2,n1}i\in\{1,2,\lfloor\frac{n}{2}\rfloor\,\lceil\frac{n}{2}\rceil+1,n-3,n-2,n-1\}, there are some results have been given by Xu, Li and Sun et al., respectively. In 2021, Luo and Guo [Discrete Math., 345 (2022) 112778] determined all graphs in Gn,n4\mathcal{G}_{n,n-4} having the minimum spectral radius. In this paper, we characterize the graphs in Gn,n4\mathcal{G}_{n,n-4} having the minimum and the maximum AαA_\alpha spectral radius for α[12,1)\alpha\in[\frac{1}{2},1), respectively.

Keywords

Cite

@article{arxiv.2210.16466,
  title  = {The $A_\alpha$ spectral radius with given independence number $n-4$},
  author = {Xichan Liu and Ligong Wang},
  journal= {arXiv preprint arXiv:2210.16466},
  year   = {2022}
}