Sufficient dyadic conditions are obtained for functions in the Lebesgue space L^p ([0, +) ) with 1 p 2, ensuring the integrability of their Fourier-Walsh transforms. These conditions are expressed in terms of moduli of smoothness and are shown to be sharp. As a result, a recent result established by Platonov in this framework is deduced.
Othman Tyr (Wed,) studied this question.