Approximation by Riesz means of hexagonal Fourier series
Summary: Let \(f\) be an \(H\)-periodic (periodic with respect to the hexagon lattice) Hölder continuous function of two real variables. The error \(\| f-R_{n}( p_{k};f) \|\) is estimated in the uniform norm and in the Hölder norm, where \((p_{k})\) is a sequence of numbers such that \(0 < p_{0} \leq p_{1}\leq \cdots\) and \(R_{n} (p_{k};f)\) is the \(n\)th Riesz mean of hexagonal Fourier series of \(f\) with respect to \((p_{k})\).
scientific article; zbMATH DE number 6684915