Exact order of approximation of periodic functions by one nonclassical method of summation of Fourier series

• Datum: 2012
• Hauptverfasser: Kotova, O. V., Trigub, R. M., Котова, О. В., Тригуб, Р. М.
• Format: Artikel
• Sprache: Russisch; Englisch
• Veröffentlicht: Institute of Mathematics, NAS of Ukraine 2012
• Online Zugang: https://umj.imath.kiev.ua/index.php/umj/article/view/2631
• Назва журналу: Ukrains’kyi Matematychnyi Zhurnal

By using an exact estimate for approximation by known trigonometric polynomials, we strengthen a Jackson-type theorem. Moreover, we determine the exact order of approximation of some periodic functions by these polynomials. For this purpose, we introduce a special modulus of smoothness.