Approximation by matrix means of hexagonal Fourier series in the generalized Ho ̈lder metric

Abstract

This paper estimates the degree of approximation of the function f , which is periodic with respect to the hexagon lattice by matrix means T(A)(f) of its hexagonal Fourier series in the generalized Ho ̈lder

metric, where A is a lower triangular infinite matrix of nonnegative real numbers with nonincreasing row.