On the best polynomial approximation in the space L2 and widths of some classes of functions

• Дата: 2012
• Автори: Vakarchuk, S. B., Zabutnaya, V. I., Вакарчук, С. Б., Забутная, В. И.
• Формат: Стаття
• Мова: Російська; Англійська
• Опубліковано: Institute of Mathematics, NAS of Ukraine 2012
• Онлайн доступ: https://umj.imath.kiev.ua/index.php/umj/article/view/2637
• Назва журналу: Ukrains’kyi Matematychnyi Zhurnal

We consider the problem of the best polynomial approximation of $2\pi$-periodic functions in the space $L_2$ in the case where the error of approximation $E_{n-1}(f)$ is estimated in terms of the $k$th-order modulus of continuity $\Omega_k(f)$ in which the Steklov operator $S_h f$ is used instead of...