Strongly regular graphs satisfying the 4-vertex condition
arXiv:2107.00076
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.
19 pages; accepted in Combinatorica