Pointwise analog of the Ste\v{c}kin approximation theorem

TL;DR

This paper establishes a pointwise version of Stecin's approximation theorem using de la Valle9e-Poussin means and also derives related results on norm approximation.

Contribution

It introduces a pointwise approximation theorem analogous to Stecin's, extending classical results to pointwise convergence.

Findings

Proves the pointwise approximation theorem for de la Valle9e-Poussin means.

Derives results on approximation in norm.

Extends classical approximation theory results.

Abstract

We show the pointwise version of the Ste\v{c}kin theorem on approximation by de la Vall\'ee-Poussin means. The result on norm approximation is also derived.