Estimates of approximation characteristics and properties of operators of the best approximation for the classes of periodic functions in the space $B_{1,1}$

• Date: 2021
• Main Authors: Romanyuk, A. S., Yanchenko, S. Ya., Романюк, А. С., Янченко, С. Я.
• Format: Article
• Language: Ukrainian
• Published: Institute of Mathematics, NAS of Ukraine 2021
• Online Access: https://umj.imath.kiev.ua/index.php/umj/article/view/6755
• Journal Title: Ukrains’kyi Matematychnyi Zhurnal

UDC 517.51 We obtain the exact-order estimates for orthoprojection widths and similar approximation characteristics of the Sobolev classes $W^{\boldsymbol{r}}_{p,\boldsymbol{\alpha}}$ and Nikol'skii–Besov classes $B^{\boldsymbol{r}}_{p,\theta}$ of periodic functions of one and several varia...