On exact order estimates of N-widths of classes of functions analytic in a simply connected domain

• Date: 1996
• Main Authors: Vakarchuk, S. B., Вакарчук, С. Б.
• Format: Article
• Language: Russian; English
• Published: Institute of Mathematics, NAS of Ukraine 1996
• Online Access: https://umj.imath.kiev.ua/index.php/umj/article/view/5318
• Journal Title: Ukrains’kyi Matematychnyi Zhurnal

In the spaces E q(Ω), 1 < q < ∞, introduced by Smirnov, we obtain exact order estimates of projective and spectral n-widths of the classes W r E p(Ω) and W r E p(Ω)Ф in the case where p and q are not equal. We also indicate extremal subspaces and operators for the approximative values...