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The Aα-spectral radius of nonregular graphs (digraphs) and maximum degree (outdegree)
Discrete Optimization ( IF 1.1 ) Pub Date : 2022-12-24 , DOI: 10.1016/j.disopt.2022.100758
Qixuan Yuan , Ruifang Liu , Jinjiang Yuan

For 0α<1, let Aα(G)=αD(G)+(1α)A(G) be the Aα-matrix of G, where D(G) is the diagonal degree matrix of G and A(G) is the adjacency matrix of G Let λα(G) denote the Aα-spectral radius of a graph G. Let G be a k-connected nonregular graph with n vertices, m edges, maximum degree Δ and minimum degree δ. In this paper, we show that Δλα(G)>(1α)(nΔ2m)k2(nΔ2m)(n1)2(Δk+1)(nk1)+(1α)nk2,which extends the result on the spectral radius of Xue and Liu (0000) and improves the result on the signless Laplacian spectral radius of Shiu et al. (2017). Furthermore, we also prove that Δλα(G)>(1α)(nΔ2m)k2(nΔ2m)(nΔ+2k2)(nδ1)+k2+(1α)nk2,which extends the result on the signless Laplacian spectral radius of Ning et al. (2018).

Let Γ be a k-strong nonregular digraph of order n, size m, and maximum outdegree Δ+. For 0α<1, let Aα(Γ)=αD(Γ)+(1α)A(Γ) be the Aα-matrix of Γ, where D(Γ) is the diagonal matrix of its vertex outdegrees and A(Γ) is the adjacency matrix of Γ. Denote by λα(Γ) the Aα-spectral radius of a digraph Γ. We prove that Δ+λα(Γ)>(1α)(nΔ+m)k22(nΔ+m)(n1)2(Δ+k+1)(nk1)+(1α)nk2,which improves the result of Xi and Wang (2020). In the end of the paper, related problem is mentioned.



中文翻译:

非常规图(digraph)的Aα-谱半径和最大度(outdegree)

为了0α<1个, 让一种α(G)=α(G)+(1个α)一种(G)成为一种α-矩阵G, 在哪里(G)是的对角线度矩阵G一种(G)是邻接矩阵Gλα(G)表示一种α-图的谱半径G. 让G是一个k-连接的非常规图n顶点,边缘,最大程度和最低学历δ. 在本文中,我们表明λα(G)>(1个α)(n2个)k2个(n2个)(n1个)2个(k+1个)(nk1个)+(1个α)nk2个,它扩展了 Xue 和 Liu (0000) 谱半径的结果,改进了 Shiu 等人的无符号拉普拉斯谱半径的结果。(2017)。此外,我们还证明λα(G)>(1个α)(n2个)k2个(n2个)(n+2个k2个)(nδ1个)+k2个+(1个α)nk2个,这扩展了 Ning 等人的无符号拉普拉斯谱半径的结果。(2018)。

Γ是一个k-强非常规有序有向图n, 尺寸, 和最大出度+. 为了0α<1个, 让一种α(Γ)=α(Γ)+(1个α)一种(Γ)成为一种α-矩阵Γ,在哪里(Γ)是顶点出度的对角矩阵,一种(Γ)是邻接矩阵Γ.表示为λα(Γ)一种α-有向图的谱半径Γ. 我们证明+λα(Γ)>(1个α)(n+)k2个2个(n+)(n1个)2个(+k+1个)(nk1个)+(1个α)nk2个,这改进了 Xi 和 Wang (2020) 的结果。在论文的最后,提到了相关问题。

更新日期:2022-12-25
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