Université d'Artois, Faculté Jean Perrin, rue Jean Souvraz S.P. 18 62307 Lens cedex, France ; Universidad de Sevilla, Faculdad de Matematica, Apdo 1160, 41080 Sevilla, Spain
Abstract:
The aim of this paper is to prove that for every , every -Rider set is a -Sidon set for all This gives some positive answers for the union problem of -Sidon sets. We also obtain some results on the behavior of the Fourier coefficient of a measure with spectrum in a -Rider set.