2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/163965We discuss some properties of Jacobi fields that do not involve assumptions on the curvature endomorphism. We compare indices of different spaces of Jacobi fields and give some applications to Riemannian geometry.10 Pages, typos corrected, references addedDifferential Geometry34C10, 53C20text