Un théorème de Helson pour des séries de Walsh
arXiv:0709.4381
Abstract
Extension to Walsh series of theorems of Helson and Katznelson on trigonometric series, saying that a trigonometric series whose partial sums are positive has its coefficients tend to zero but is not necessarily a Fourier-Lebesgue series
The paper was written for the 50th anniversary of Henry Helson's article and the 70th anniversary of Yitzhak Katznelson