English

On $\alpha$-adjacency energy of graphs and Zagreb index

Combinatorics 2021-07-20 v1 Spectral Theory

Abstract

Let A(G)A(G) be the adjacency matrix and D(G)D(G) be the diagonal matrix of the vertex degrees of a simple connected graph GG. Nikiforov defined the matrix Aα(G)A_{\alpha}(G) of the convex combinations of D(G)D(G) and A(G)A(G) as Aα(G)=αD(G)+(1α)A(G)A_{\alpha}(G)=\alpha D(G)+(1-\alpha)A(G), for 0α10\leq \alpha\leq 1. If ρ1ρ2ρn \rho_{1}\geq \rho_{2}\geq \dots \geq \rho_{n} are the eigenvalues of Aα(G)A_{\alpha}(G) (which we call α\alpha-adjacency eigenvalues of GG), the α \alpha -adjacency energy of GG is defined as EAα(G)=i=1nρi2αmnE^{A_{\alpha}}(G)=\sum_{i=1}^{n}\left|\rho_i-\frac{2\alpha m}{n}\right|, where nn is the order and mm is the size of GG. We obtain the upper and lower bounds for EAα(G)E^{A_{\alpha}}(G) in terms of order nn, size mm and Zagreb index Zg(G)Zg(G) associated to the structure of GG. Further, we characterize the extremal graphs attaining these bounds.

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Cite

@article{arxiv.2005.01037,
  title  = {On $\alpha$-adjacency energy of graphs and Zagreb index},
  author = {S. Pirzada and Bilal A. Rather and Hilal A. Ganie and Rezwan ul Shaban},
  journal= {arXiv preprint arXiv:2005.01037},
  year   = {2021}
}

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17 pages