Abstract
Given a graph G, the adjacency matrix and degree diagonal matrix of G are denoted by A(G) and D(G), respectively. In 2017, Nikiforov[24] proposed the Aα-matrix: Aα(G) = αD(G) + (1 − α)A(G), where α ∈ [0, 1]. The largest eigenvalue of this novel matrix is called the Aα-index of G. In this paper, we characterize the graphs with minimum Aα-index among n-vertex graphs with independence number i for α ∈ [0, 1), where \(i = 1,\,\,\left\lfloor {{n \over 2}} \right\rfloor,\left\lceil {{n \over 2}} \right\rceil,\,\left\lfloor {{n \over 2}} \right\rfloor + 1,n - 3,n - 2,n - 1\), whereas for i = 2 we consider the same problem for \(\alpha \in [0,{3 \over 4}]\). Furthermore, we determine the unique graph (resp. tree) on n vertices with given independence number having the maximum Aα-index with α ∈ [0, 1), whereas for the n-vertex bipartite graphs with given independence number, we characterize the unique graph having the maximum Aα-index with \(\alpha \in [{1 \over 2},1)\).
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We take this opportunity to thank the anonymous reviewers for their critical reading of the manuscript and suggestions which have immensely helped us in getting the article to its present form.
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The authors declare no conflict of interest.
This paper is supported by the Undergraduate Innovation and Entrepreneurship Grant from Central China Normal University (Grant No. 20210409037), by Industry-University-Research Innovation Funding of Chinese University (Grant No. 2019ITA03033) and by the National Natural Science Foundation of China (Grant Nos. 12171190, 11671164).
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Sun, Wt., Yan, Lx., Li, Sc. et al. Sharp Bounds on the Aα-index of Graphs in Terms of the Independence Number. Acta Math. Appl. Sin. Engl. Ser. 39, 656–674 (2023). https://doi.org/10.1007/s10255-023-1049-4
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DOI: https://doi.org/10.1007/s10255-023-1049-4