Degree of comonotone approximation of periodic functions

• Date: 2013
• Main Authors: Dzyubenko, G. A., Дзюбенко, Г. А.
• Format: Article
• Language: Ukrainian
• Published: Інститут математики НАН України 2013
• Online Access: https://trim.imath.kiev.ua/index.php/trim/article/view/142
• Journal Title: Transactions of Institute of Mathematics of NAS of Ukraine

If a continuously differentiable on a real axe $\Bbb R\ \ 2\pi - $periodic function $f$ changes its monotonicity at different fixed points $y_i\in [-\pi,\pi),\ i=1,...,2s,\ s\in\Bbb N ,$ (i.e., on $\Bbb R$ there is a set $Y:=\{y_i\}_{i\in\Bbb Z}$ of points $y_i=y_{i+2s}+2\pi $ such that on $[y_i,y_{...