Approximation of functions of many variables from the generalization Nikol'skii-Besov type classes in the uniform and integral metrics

Abstract

We obtain the exact order estimates of the approximation of the functions of many variables from the generalized Nikol'skii-Besov classes $B^{\Omega}_{p,\theta}(\mathbb{R}^d)$ by sums of de la Vallee Poussin type in the metrics space $L_{\infty}(\mathbb{R}^d)$ and $L_{1}(\mathbb{R}^d)$. These classes of functions for some given $\Omega$ coincide with the well-known classical Nikol'skii-Besov isotropic classes.