Estimations of the Best Approximations for the Classes of Infinitely Differentiable Functions in Uniform and Integral Metrics

• Дата: 2014
• Автори: Serdyuk, A. S., Stepanyuk, T. A., Сердюк, А. С., Степанюк, Т. А.
• Формат: Стаття
• Мова: Українська; Англійська
• Опубліковано: Institute of Mathematics, NAS of Ukraine 2014
• Онлайн доступ: https://umj.imath.kiev.ua/index.php/umj/article/view/2215
• Назва журналу: Ukrains’kyi Matematychnyi Zhurnal

We establish uniform (with respect to the parameter p, 1 ≤ p ≤ ∞) upper estimations of the best approximations by trigonometric polynomials for the classes C β,p ψ of periodic functions generated by sequences ψ(k) vanishing faster than any power function. The obtained estimations are exact in...