2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/138842Grid condition and Sidon sets. The grid condition stated by the author in 1957 as a necessary condition for a set of integers to be a Sidon set is neither improvable nor sufficient ; explanations and stronger statements are provided.Le point de départ de l'article est le colloque tenu à Orsay en 2005 en l'honneur de Myriam Déchamps-GondimClassical Analysis and ODEs42A55text