Bivariate P -polynomial association schemes
Pierre-Antoine Bernard, Nicolas Crampé, Loïc Poulain d’Andecy, Luc Vinet, Meri Zaimi · Algebraic Combinatorics · 2024
Bivariate P -polynomial association scheme of type ( α , β ) are defined as a generalization of the P -polynomial association schemes. This generalization is shown to be equivalent to a set of conditions on the intersection parameters. A number of known higher rank association schemes are seen to belong to this broad class. Bivariate Q -polynomial association schemes are similarly defined.