On trigonometric approximation in weighted lorentz spaces using norlund and riesz submethods

Abstract

In this study, we obtain the degree of approximation by the Norlund and Riesz submethods of the partial sums of the Fourier series of derivatives of functions in the weighted Lorentz spaces with Muckenhoupt weights. Therefore we generalize the theorems given in [22] to their sharper approximation versions with weaker conditions.