English

Strongly regular graphs satisfying the 4-vertex condition

Combinatorics 2022-09-09 v2

Abstract

We survey the area of strongly regular graphs satisfying the 4-vertex condition and find several new families. We describe a switching operation on collinearity graphs of polar spaces that produces cospectral graphs. The obtained graphs satisfy the 4-vertex condition if the original graph belongs to a symplectic polar space.

Keywords

Cite

@article{arxiv.2107.00076,
  title  = {Strongly regular graphs satisfying the 4-vertex condition},
  author = {A. E. Brouwer and F. Ihringer and W. M. Kantor},
  journal= {arXiv preprint arXiv:2107.00076},
  year   = {2022}
}

Comments

19 pages; accepted in Combinatorica

R2 v1 2026-06-24T03:46:57.683Z