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Title:
A Note on Energy and Sombor Energy of Graphs
Authors:
Bilal Ahmad Rather, Muhammad Imran
doi:
Volume
89
Issue
2
Year
2023
Pages
467-477
Abstract For a graph \(G\) with \(V(G)=\{v_{1},v_{2},\dots, v_{n}\}\) and degree sequence \((d_{v_{1}},d_{v_{2}},\dots,d_{v_{n}})\), the adjacency matrix \(A(G)\) of \(G\) is a \((0,1)\) square matrix of order \(n\) with \(ij\)-th entry 1, if \(v_{i}\) is adjacent to \(v_{j}\) and 0, otherwise. The Sombor matrix \(S(G)=(s_{ij})\) is a square matrix of order \(n\), where \(s_{ij}=\sqrt{d_{v_{i}}^{2}+d_{v_{j}}^{2}}\), whenever \(v_{i}\) is adjacent to \(v_{j}\), and 0, otherwise. The sum of the absolute values of the eigenvalues of \(A(G)\) is the energy, while the sum of the absolute eigenvalues of \(S(G)\) is the Sombor energy of \(G\). In this note, we provide counter examples to the upper bound of Theorem 18 in [13] and Theorem 1 in [16].

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