English

Multiplicity of eigenvalues of cographs

Combinatorics 2018-01-30 v1

Abstract

Motivated by the linear time algorithm that locates the eigenvalues of a cograph G [10], we investigate the multiplicity of eigenvalue for \lambda \neq -1,0. For cographs with balanced cotrees we determine explicitly the highest value for the multiplicity.The energy of a graph is defined as the sum of absolute values of the eigenvalues. A graph G on n vertices is said to be borderenergetic if its energy equals the energy of the complete graph Kn. We present families of non-cospectral and borderenergetic cographs.

Keywords

Cite

@article{arxiv.1801.08972,
  title  = {Multiplicity of eigenvalues of cographs},
  author = {Luiz Emilio Allem and Fernando Tura},
  journal= {arXiv preprint arXiv:1801.08972},
  year   = {2018}
}