English

Exploring new upper and lower bounds for the $A_{\alpha}$-energy of graphs

Combinatorics 2026-03-26 v1

Abstract

Let GG be a graph on nn vertices and mm edges. For α[0,1]\alpha \in [0,1], the AαA_{\alpha}-matrix of GG is defined as Aα(G)=αD(G)+(1α)A(G)A_{\alpha}(G) = \alpha D(G) + (1- \alpha) A(G), where A(G)A(G) is the adjacency matrix and D(G)D(G) is the degree diagonal matrix of GG. If ρ1ρ2ρn\rho_1 \geq \rho_2 \ldots \geq \rho_n are the eigenvalues of Aα(G)A_{\alpha}(G), the AαA_{\alpha}-energy of GG is defined as EAα(G)=i=1nρi2αmnE_{A_{\alpha}}(G) = \sum_{i=1}^{n} |\rho_i -\frac{2\alpha m}{n}|. In this paper, we present novel upper and lower bounds for EAα(G)E_{A_\alpha}(G) in terms of standard graph invariants, showing that each bound is sharp and identifying the specific graphs attaining them. For selected bounds, we provide brief comparative analysis with existing results, observing improved estimates. Furthermore, we establish new relations between EAα(G)E_{A_\alpha}(G) and other well known graph energies, including adjacency, Laplacian, as well as the adjacency energy of the line graph.

Keywords

Cite

@article{arxiv.2603.23920,
  title  = {Exploring new upper and lower bounds for the $A_{\alpha}$-energy of graphs},
  author = {Mainak Basunia and Pratima Panigrahi},
  journal= {arXiv preprint arXiv:2603.23920},
  year   = {2026}
}