English

Design switching on graphs

Combinatorics 2025-08-18 v1

Abstract

We show that each (r, lambda)-design yields a class of switching methods that can be used produce cospectral graphs. We use this to explain several specific switching methods such as Godsil-McKay (GM) switching and Wang-Qiu-Hu (WQH) switching.

Cite

@article{arxiv.2508.11523,
  title  = {Design switching on graphs},
  author = {Ferdinand Ihringer and Robin Simoens},
  journal= {arXiv preprint arXiv:2508.11523},
  year   = {2025}
}
R2 v1 2026-07-01T04:52:01.678Z