ASYMPTOTICS OF THE VALUES OF APPROXIMATIONS IN THE MEAN FOR CLASSES OF DIFFERENTIABLE FUNCTIONS BY USING BIHARMONIC POISSON INTEGRALS

Abstract

We obtain complete asymptotic expansions for the exact upper bounds of the approximations of functions from the classes Wr 1 , r ∈ N, and Wr 1 , r ∈N \ {1}, by their biharmonic Poisson integrals.