Jackson inequality for Banach spaces on the sphere
Using certain new moduli of smoothness introduced by \textit{Z.~Ditzian} [J. Anal. Math. 79, 189--200 (1999; Zbl 0981.41004)], the authors prove Jackson estimates for the approximation on the sphere by spherical polynomials. The results are presented separately for even and odd dimensions, where the results for even dimensions are more general. For the former case, a strong converse inequality is given as well.
scientific article; zbMATH DE number 5355078