2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/159659We define a group of relative differential K-characters associated with a smooth map between two smooth compact manifolds. We show that this group fits into a short exact sequence as in the non-relative case. Some secondary geometric invariants are expressed in this theory.Published in SIGMA (Symmetry, Integrability and Geometry: Methods and Applications) at http://www.emis.de/journals/SIGMA/K-Theory and HomologyAlgebraic Topologytext