Orthogonal polynomials and partial differential equations on the unit ball

Orthogonal polynomials of degree n with respect to the weight function W μ (x) = (1 - ∥x∥ 2 ) μ on the unit ball in R are known to satisfy the partial differential equation [Δ- ?x, ∇? 2 - (2μ + d) ?x, ∇?] P = -n(n + 2μ + d)P for μ > -1. The singular case of μ = -1, -2, ... is studied in this paper. Explicit polynomial solutions are constructed and the equation for ν = -2, -3, ... is shown to have complete polynomial solutions if the dimension d is odd. The orthogonality of the solution is also discussed.