Abstract
We consider two-dimensional convolution operators with general kernel functions and give a sufficient condition for the two-parameter maximal operator to be bounded from the dyadic martingale Hardy space Hp to Lp. Especially, the boundedness of the maximal operator of the twoparameter dyadic derivative of the dyadic integral function and the maximal operator of the two-parameter Cesàro means are verified. As a consequence we obtain that every function f ∊ L log+ L[O, 1)2 is Cesho summable and the dyadic integral of it is dyadically differentiable.