On approximation of the separately continuous functions $2\pi$-periodical in relation to the second variable

Using Jackson's and Bernstein's operators we prove that for every topological space $X$ and an arbitrary separately continuous function $f: X \times \mathbb{R}\rightarrow \mathbb{R}$, $2\pi$-periodical in relation to the second variable, there exists such sequence of jointly continuous f...

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Bibliographic Details
Main Authors: H. A. Voloshyn, V. K. Maslyuchenko
Format: Article
Language:English
Published: Vasyl Stefanyk Precarpathian National University 2013-01-01
Series:Karpatsʹkì Matematičnì Publìkacìï
Online Access:http://journals.pu.if.ua/index.php/cmp/article/view/34
Description
Summary:Using Jackson's and Bernstein's operators we prove that for every topological space $X$ and an arbitrary separately continuous function $f: X \times \mathbb{R}\rightarrow \mathbb{R}$, $2\pi$-periodical in relation to the second variable, there exists such sequence of jointly continuous functions $f_n: X\times \mathbb{R}\rightarrow \mathbb{R}$ such that functions $f_n^x=f_n(x, \cdot): \mathbb{R}\rightarrow \mathbb{R}$ are trigonometric polynomials and $f_n^x\to f^x$ uniformly on $\mathbb{R}$ for every $x\in X$.
ISSN:2075-9827
2313-0210