“…It is hard to overstate the role that the classical orthogonal polynomials have played in mathematics and physics over the last few centuries. Recently, there have been interesting multivariate extensions of this theory based on connections with quantum integrable systems, representation theory and algebraic combinatorics, see for instance [3,4,5,7,11,28,31] and the references therein. In particular, the work [25] describing the irreducible representations of the symmetry algebra of the generic superintegrable system on the 3-sphere suggested that spectral properties of multivariate extensions of the classical orthogonal polynomials were intimately related to first integrals of superintegrable systems.…”