Almost coconvex approximation of continuous periodic functions

• Date: 2019
• Main Authors: Dzyubenko, H. A., Дзюбенко, Г. А.
• Format: Article
• Language: Ukrainian
• Published: Institute of Mathematics, NAS of Ukraine 2019
• Online Access: https://umj.imath.kiev.ua/index.php/umj/article/view/1444
• Journal Title: Ukrains’kyi Matematychnyi Zhurnal

If a $2\pi$ -periodic function $f$ continuous on the real axis changes its convexity at $2s, s \in N$, points $y_i : \pi \leq y_{2s} < y_{2s-1} < . . . < y_1 < \pi$ , and, for all other $i \in Z$, $y_i$ are periodically defined, then, for every natural $n \geq N_{y_...