2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/155960We show that if A is a set having small subtractive doubling in an abelian group, that is |A-A|< K|A|, then there is a polynomially large subset B of A-A so that the additive energy of B is large than (1/K)^{1 - ε) where epsilon is a positive, universal exponent. (1/37 seems to suffice.)12 pagesCombinatoricsClassical Analysis and ODEstext