Approximation of Continuous Functions by Matrix Means of Hexagonal Fourier Series

Some estimates for the degree of approximation by matrix means of hexagonal Fourier series of H\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathbf {H}$$\end{document}-periodic continuous functions are obtained. The degree of approximation of H\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathbf {H}$$\end{document}-periodic Hölder continuous functions by these means is investigated in uniform and Hölder norms and some results about Riesz and Nörlund means of hexagonal Fourier series are concluded.