Let $ A(G) $ and $ D(G) $ be the adjacency matrix and the degree diagonal matrix of a graph $ G $, respectively. For any real number $ \alpha \in[0, 1] $, Nikiforov defined the $ A_{\alpha} $-matrix of a graph $ G $ as $ A_{\alpha}(G) = \alpha D(G)+(1-\alpha)A(G) $. Let $ S_k(A_{\alpha}(G)) $ be the sum of the $ k $ largest eigenvalues of $ A_{\alpha}(G) $. In this paper, some bounds on $ S_k(A_{\alpha}(G)) $ are obtained, which not only extends the results of the sum of the $ k $ largest eigenvalues of the adjacency matrix and signless Laplacian matrix, but it also gives new bounds on graph energy.
Citation: Zhen Lin. On the sum of the largest $ A_{\alpha} $-eigenvalues of graphs[J]. AIMS Mathematics, 2022, 7(8): 15064-15074. doi: 10.3934/math.2022825
Let $ A(G) $ and $ D(G) $ be the adjacency matrix and the degree diagonal matrix of a graph $ G $, respectively. For any real number $ \alpha \in[0, 1] $, Nikiforov defined the $ A_{\alpha} $-matrix of a graph $ G $ as $ A_{\alpha}(G) = \alpha D(G)+(1-\alpha)A(G) $. Let $ S_k(A_{\alpha}(G)) $ be the sum of the $ k $ largest eigenvalues of $ A_{\alpha}(G) $. In this paper, some bounds on $ S_k(A_{\alpha}(G)) $ are obtained, which not only extends the results of the sum of the $ k $ largest eigenvalues of the adjacency matrix and signless Laplacian matrix, but it also gives new bounds on graph energy.
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