We investigate the use of non-homogeneous spherical poly-nomials for the approximation of functions deened on the sphere S 2. A spherical polynomial is the restriction to S 2 of a polynomial in the three coordinates x; y; z of R 3. Let P d be the space of spherical polynomials with degree d. We show that P d is the direct sum of H d and H d?1 , where H d denotes the space of homogeneous degree-...
