English

On NP-hard graph properties characterized by the spectrum

Combinatorics 2020-01-28 v2

Abstract

Properties of graphs that can be characterized by the spectrum of the adjacency matrix of the graph have been studied systematically recently. Motivated by the complexity of these properties, we show that there are such properties for which testing whether a graph has that property can be NP-hard (or belong to other computational complexity classes consisting of even harder problems). In addition, we discuss a possible spectral characterization of some well-known NP-hard problems. In particular, for every integer k6k\geq 6 we construct a pair of kk-regular cospectral graphs, where one graph is Hamiltonian and the other one not.

Keywords

Cite

@article{arxiv.1912.07061,
  title  = {On NP-hard graph properties characterized by the spectrum},
  author = {Omid Etesami and Willem H. Haemers},
  journal= {arXiv preprint arXiv:1912.07061},
  year   = {2020}
}
R2 v1 2026-06-23T12:46:25.101Z