English

On sign-symmetric signed graphs

Combinatorics 2020-03-24 v1

Abstract

A signed graph is said to be sign-symmetric if it is switching isomorphic to its negation. Bipartite signed graphs are trivially sign-symmetric. We give new constructions of non-bipartite sign-symmetric signed graphs. Sign-symmetric signed graphs have a symmetric spectrum but not the other way around. We present constructions of signed graphs with symmetric spectra which are not sign-symmetric. This, in particular answers a problem posed by Belardo, Cioab\u{a}, Koolen, and Wang (2018).

Keywords

Cite

@article{arxiv.2003.09981,
  title  = {On sign-symmetric signed graphs},
  author = {Ebrahim Ghorbani and Willem H. Haemers and Hamid Reza Maimani and Leila Parsaei Majd},
  journal= {arXiv preprint arXiv:2003.09981},
  year   = {2020}
}
R2 v1 2026-06-23T14:23:18.294Z