2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/118005Let $A$ be a subset of $\mathbb{Z} / N\mathbb{Z}$ and let $\mathcal{R}$ be the set of large Fourier coefficients of $A$. Properties of $\mathcal{R}$ have been studied in works of M.-- C. Chang, B. Green and the author. In the paper we obtain some new results on sets of large exponential sums.27 pagesNumber TheoryCombinatoricstext