Reconstructing a generalized quadrangle from the Penttila-Williford class association scheme
arXiv:2205.05350
Abstract
Penttila and Williford constructed a class association scheme from a generalized quadrangle with a doubly subtended subquadrangle. We show that an association scheme with appropriate parameters and satisfying some assumption about maximal cliques must be the Penttila-Williford scheme.