English

Partial characterization of graphs having a single large Laplacian eigenvalue

Combinatorics 2017-10-05 v1

Abstract

The parameter σ(G)\sigma(G) of a graph GG stands for the number of Laplacian eigenvalues greater than or equal to the average degree of GG. In this work, we address the problem of characterizing those graphs GG having σ(G)=1\sigma(G)=1. Our conjecture is that these graphs are stars plus a (possible empty) set of isolated vertices. We establish a link between σ(G)\sigma(G) and the number of anticomponents of GG. As a by-product, we present some results which support the conjecture, by restricting our analysis to some classes of graphs.

Keywords

Cite

@article{arxiv.1710.01710,
  title  = {Partial characterization of graphs having a single large Laplacian eigenvalue},
  author = {L. Emilio Allem and Antonio Cafure and Ezequiel Dratman and Luciano N. Grippo and Martín D. Safe and Vilmar Trevisan},
  journal= {arXiv preprint arXiv:1710.01710},
  year   = {2017}
}

Comments

10 pages

R2 v1 2026-06-22T22:03:49.305Z