2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/174167We investigate the notion of H-subdifferential and H-normal map of a function on the Heisenberg group, based on its sub-Riemannian structure. In particular, a characterization of the convexity of a function is given via the nonemptiness of the H-subdifferential at every point.Differential Geometry52A01 (Primary); 26B25, 22E15 (Secondary)text