“…This was accomplished for the first time in the case of the complex projective plane P 2 (C) = SU(3)/U(2) in [5]. This seminal work gave rise to a series of papers including [6,7,8,10,14,15,16,17,18,19], where one considers matrix valued spherical functions associated to a compact symmetric pair (G, K) of rank one, arriving at sequences of matrix valued orthogonal polynomials of one real variable satisfying an explicit three-term recursion relation, which are also eigenfunctions of a second order matrix differential operator (bispectral property).…”