English

Constructing cospectral graphs by unfolding non-bipartite graphs

Combinatorics 2024-11-22 v2

Abstract

In 2010, Butler introduced the unfolding operation on a bipartite graph to produce two bipartite graphs, which are cospectral for the adjacency and the normalized Laplacian matrices. In this article, we describe how the idea of unfolding a bipartite graph with respect to another bipartite graph can be extended to nonbipartite graphs. In particular, we describe how unfoldings involving reflexive bipartite, semi-reflexive bipartite, and multipartite graphs are used to obtain cospectral nonisomorphic graphs for the adjacency matrix.

Keywords

Cite

@article{arxiv.2401.03035,
  title  = {Constructing cospectral graphs by unfolding non-bipartite graphs},
  author = {M. Rajesh Kannan and Shivaramakrishna Pragada and Hitesh Wankhede},
  journal= {arXiv preprint arXiv:2401.03035},
  year   = {2024}
}

Comments

arXiv admin note: text overlap with arXiv:2110.09034

R2 v1 2026-06-28T14:09:51.980Z