English

On the extreme complexity of certain nearly regular graphs

Combinatorics 2025-02-12 v1

Abstract

The complexity of a graph is the number of its labeled spanning trees. It is demonstrated that the seven known triangle-free strongly regular graphs, such as the Higman-Sims graph, are graphs of maximal complexity among all graphs of the same order and degree; their complements are shown to be of minimal complexity. A generalization to nearly regular graphs with two distinct eigevalues of the Laplacian is presented. Conjectures and applications of these results to biological problems on neuronal activity are described.

Keywords

Cite

@article{arxiv.2502.06886,
  title  = {On the extreme complexity of certain nearly regular graphs},
  author = {Gregory P Constantine and Gregory C Magda},
  journal= {arXiv preprint arXiv:2502.06886},
  year   = {2025}
}

Comments

arXiv admin note: text overlap with arXiv:2501.18019