2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/35789Relying on the general theory of Lie derivatives a new geometric definition of Lie derivative for general spinor fields is given, more general than Kosmann's one. It is shown that for particular infinitesimal lifts, i.e. for Kosmann vector fields, our definition coincides with the definition given by Kosmann more than 20 years ago.10 pages, Plain TEXGeneral Relativity and Quantum Cosmologytext