Triangular Fej\'er Summability of Two-Dimensional Walsh-Fourier series

Abstract

It is proved that the operators $\sigma_{n}^{\bigtriangleup}$ of the triangular-Fej{\'e}r-means of a two-dimensional Walsh--Fourier series are uniformly bounded from the dyadic Hardy space $H_{p}$ to $L_{p}$ for all $% 4/5<p\leq \infty $.