The notion of multivariate P-and Q-polynomial association scheme has been introduced
recently, generalizing the well-known univariate case. Numerous examples of such …

The notion of factorized $ A_2 $-Leonard pair is introduced. It is defined as a rank 2 Leonard
pair, with actions in certain bases corresponding to the root system of the Weyl group $ A_2 …

This paper offers a review of recent studies on the entanglement of free-fermion systems on
graphs that take advantage of methods pertaining to signal processing and algebraic …

An association scheme is P-polynomial if and only if it consists of the distance matrices of a
distance-regular graph. Recently, bivariate P-polynomial association schemes of type (α, β) …

The study of P-polynomial association schemes (distance-regular graphs) and Q-polynomial
association schemes, and in particular P-and Q-polynomial association schemes, has been …

Bivariate Griffiths polynomials of Racah type are constructed from univariate Racah
polynomials. The bispectral properties of the former are deduced from simple properties of …

Let Γ= Γ (n, m) denote the Doob graph formed by the Cartesian product of the nth Cartesian
power of the Shrikhande graph and the mth Cartesian power of the complete graph on four …

The bivariate $ P $-and $ Q $-polynomial structures of association schemes based on
attenuated spaces are examined using recurrence and difference relations of the bivariate …

New bivariate Griffiths polynomials of $ q $-Racah type are introduced and characterized.
They generalize the polynomials orthogonal on the multinomial distribution introduced by R …

Let $ K\leq H $ be two finite groups and let $ C\leq A $ be two finite abelian groups, with $ H
$ acting on $ A $ as a group of isomorphisms admitting $ C $ as a $ K $-invariant subgroup …