On the minimum spectral radius of connected graphs of given order and size
Combinatorics
2025-03-04 v2 Discrete Mathematics
Abstract
In this paper, we study a question of Hong from 1993 related to the minimum spectral radii of the adjacency matrices of connected graphs of given order and size. Hong asked if it is true that among all connected graphs of given number of vertices and number of edges , the graphs having minimum spectral radius (the minimizer graphs) must be almost regular, meaning that the difference between their maximum degree and their minimum degree is at most one. In this paper, we answer Hong's question positively for various values of and and in several cases, we determined the graphs with minimum spectral radius.
Cite
@article{arxiv.2405.15046,
title = {On the minimum spectral radius of connected graphs of given order and size},
author = {Sebastian M. Cioabă and Vishal Gupta and Celso Marques},
journal= {arXiv preprint arXiv:2405.15046},
year = {2025}
}
Comments
22 pages, 6 figures, revised paper taking into consideration the comments from the referees