Approximation by Nörlund means of double Fourier series for Lipschitz functions
The authors study the rate of uniform approximation by Nörlund means of the rectangular partials sums of the double Fourier series of the rectangular partial sums of the double Fourier series of a function f(x,y) belonging to the class Lip \(\alpha\), \(0<\alpha \leq 1\), on the two- dimensional torus \(-\pi <x,y\leq \pi\). As a special case they also obtain the rate of uniform approximation by double Cesàro means.
scientific article; zbMATH DE number 4036385
scientific article