English

Switching graphs and Hadamard matrices

Combinatorics 2024-10-15 v1

Abstract

Local operations of combinatorial structures (graphs, Hadamard matrices, codes, designs) that maintain the basic parameters unaltered, have been widely used in the literature under the name of switching. We show an equivalence between two switching methods to construct inequivalent Hadamard matrices, which were proposed by Orrick [SIAM Journal on Discrete Mathematics, 2008], and the switching method for constructing cospectral graphs which was introduced by Godsil and McKay [Aequationes Mathematicae, 1982].

Keywords

Cite

@article{arxiv.2410.10638,
  title  = {Switching graphs and Hadamard matrices},
  author = {Aida Abiad and Louka Peters},
  journal= {arXiv preprint arXiv:2410.10638},
  year   = {2024}
}
R2 v1 2026-06-28T19:20:49.443Z