2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/72735Killing forms on Riemannian manifolds are differential forms whose covariant derivative is totally skew-symmetric. We show that on a compact manifold with holonomy G2 or Spin7 any Killing form has to be parallel. The main tool is a universal Weitzenboeck formula. We show how such a formula can be obtained for any given holonomy group and any representation defining a vector bundle.15 pagesDifferential Geometry53C55text