2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/77110Ray Singer torsion is a numerical invariant associated with a compact Riemannian manifold equipped with a flat bundle and a Hermitian structure on this bundle. In this note we show how one can remove the dependence on the Riemannian metric and on the Hermitian structure with the help of a base point and of an Euler structure, in order to obtain a topological invariant. A numerical invariant for an Euler structure and additional data is also constructed.10 pages, AMSTEX,typos corrected, thanks addedDifferential Geometry57Q10, 58G26text