Order estimates of functionals in terms of which the best $n$-term approximations of classes ${\cal F}_{q,r}^{\psi}$ are expressed.

Abstract

We obtain the exact order estimates of the functionals, which are the expressions of best $n$-term approximations of the classes of functions of several variables ${\cal F}_{q,r}^{\psi}$. The obtained results are applied to finding the approximative characteristics in the spaces $S^p$ and $L_p$