Bounds on the $A_{\alpha}$-Spectral Radius of a $C_3$-Free Graph
Received:October 04, 2020  Revised:January 03, 2021
Key Words: $C_3$-free graph   $k$-cycle graph   $A_{\alpha}$-spectral radius   bound  
Fund Project:Supported by the National Natural Science Foundation of China (Grant Nos.12071411; 12171222).
Author NameAffiliation
Dongxia ZHU School of Mathematics and Statistics, Qinghai Normal University, Qinghai 810008, P. R. China
School of Mathematics and Statistics, Yancheng Teachers University, Jiangsu 224002, P. R. China 
Shuguang GUO School of Mathematics and Statistics, Yancheng Teachers University, Jiangsu 224002, P. R. China 
Rong ZHANG School of Mathematics and Statistics, Yancheng Teachers University, Jiangsu 224002, P. R. China 
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Abstract:
      Let $G$ be a simple undirected graph. For any real number $\alpha \in[0,1]$, Nikiforov defined the $A_{\alpha}$-matrix of $G$ as $A_{\alpha}(G)=\alpha D(G)+(1-\alpha)A(G)$ in 2017, where $A(G)$ and $D(G)$ are the adjacency matrix and the degree diagonal matrix of $G$, respectively. In this paper, we obtain a lower bound on the $A_{\alpha}$-spectral radius of a $C_3$-free graph for $\alpha \in[0, 1)$ and a sharp upper bound on the $A_{\alpha}$-spectral radius of a $C_3$-free $k$-cycle graph for $\alpha \in[1/2, 1)$.
Citation:
DOI:10.3770/j.issn:2095-2651.2022.01.001
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