2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/193078The reduction formulas for Dirac fermions are derived, using the exact solutions of free Dirac equation on de Sitter spacetime. In the framework of the perturbation theory one studies the Green functions and derive the scatering amplitude in the first orders of perturbation theory.12 pages, no figuresHigh Energy Physics - Theorytext