English

On a generalization of the spectral Mantel's theorem

Combinatorics 2023-01-18 v1

Abstract

Mantel's theorem is a classical result in extremal graph theory which implies that the maximum number of edges of a triangle-free graph of order nn. In 1970, E. Nosal obtained a spectral version of Mantel's theorem which gave the maximum spectral radius of a triangle-free graph of order nn. In this paper, the clique tensor of a graph GG is proposed and the spectral Mantel's theorem is extended via the clique tensor. Furthermore, a sharp upper bound of the number of cliques in GG via the spectral radius of the clique tensor is obtained. And we show that the results of this paper implies that a result of Erd\H{o}s [Magyar Tud. Akad. Mat. Kutat\'{o} Int. K\"{o}zl. 7 (1962)] under certain conditions.

Keywords

Cite

@article{arxiv.2301.06423,
  title  = {On a generalization of the spectral Mantel's theorem},
  author = {Chunmeng Liu and Changjiang Bu},
  journal= {arXiv preprint arXiv:2301.06423},
  year   = {2023}
}