English

On the distribution of $A_\alpha$-eigenvalues in terms of graph invariants

Discrete Mathematics 2025-10-09 v1

Abstract

Let GG be a connected graph of order nn, and A(G)A(G) and D(G)D(G) its adjacency and degree diagonal matrices, respectively. For a parameter α[0,1]\alpha \in [0,1], Nikiforov~(2017) introduced the convex combination Aα(G)=αD(G)+(1α)A(G)A_{\alpha}(G) = \alpha D(G) + (1 - \alpha)A(G). In this paper, we investigate the spectral distribution of Aα(G)A_\alpha(G)-eigenvalues, over subintervals of the real line. We establish lower and upper bounds on the number of such eigenvalues in terms of structural parameters of GG, including the number of pendant and quasi-pendant vertices, the domination number, the matching number, and the edge covering number. Additionally, we exhibit families of graphs for which these bounds are attained. Several of our results extend known spectral bounds on the eigenvalue distributions of both the adjacency and the signless Laplacian matrices.

Keywords

Cite

@article{arxiv.2510.06933,
  title  = {On the distribution of $A_\alpha$-eigenvalues in terms of graph invariants},
  author = {Uilton Cesar Peres Junior and Carla Silva Oliveira and André Ebling Brondan},
  journal= {arXiv preprint arXiv:2510.06933},
  year   = {2025}
}