2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/74381We show that if $A=\{a_1,a_2,..., a_k\}$ is a monotone increasing set of numbers, and the differences of the consecutive elements are all distinct, then $|A+B|\geq c|A|^{1/2}|B|$ for any finite set of numbers $B$. The bound is tight up to the constant multiplier.7 pagesCombinatoricsNumber Theory05D10text