2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/115142We prove a theorem claimed in math.CA/0605519 which asserts that if A is a subset of a compact abelian group G with density of a particular (natural, although technical) form then the A(G)-norm (that is the sum of the absolute values of the Fourier transform) of the characteristic function of A cannot be too small.Classical Analysis and ODEsCombinatoricstext