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The $A_\alpha$-spectral radius and perfect matchings of graphs

Combinatorics 2021-04-12 v3

Abstract

Let α[0,1)\alpha\in[0,1), and let GG be a graph of even order nn with nf(α)n\geq f(\alpha), where f(α)=10f(\alpha)=10 for 0α1/20\leq \alpha\leq1/2, f(α)=14f(\alpha)=14 for 1/2<α2/31/2<\alpha\leq 2/3 and f(α)=5/(1α)f(\alpha)=5/(1-\alpha) for 2/3<α<12/3<\alpha<1. In this paper, it is shown that if the AαA_\alpha-spectral radius of GG is not less than the largest root of x3((α+1)n+α4)x2+(αn2+(α22α1)n2α+1)xα2n2+(5α23α+2)n10α2+15α8=0x^3 - ((\alpha + 1)n +\alpha-4)x^2 + (\alpha n^2 + (\alpha^2 - 2\alpha - 1)n - 2\alpha+1)x -\alpha^2n^2 + (5\alpha^2 - 3\alpha + 2)n - 10\alpha^2 + 15\alpha - 8=0 then GG has a perfect matching unless G=K1(Kn32K1)G=K_1\nabla(K_{n-3}\cup 2K_1). This generalizes a result of S. O [Spectral radius and matchings in graphs, Linear Algebra Appl. 614 (2021) 316--324], which gives a sufficient condition for the existence of a perfect matching in a graph in terms of the adjacency spectral radius.

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Cite

@article{arxiv.2007.06923,
  title  = {The $A_\alpha$-spectral radius and perfect matchings of graphs},
  author = {Yanhua Zhao and Xueyi Huang and Zhiwen Wang},
  journal= {arXiv preprint arXiv:2007.06923},
  year   = {2021}
}

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13 pages