2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/228307We briefly review the matter effects in case of Dirac and Majorana neutrino propagation in medium. We develop the quantum treatment of neutrinos in matter: using the generalized Dirac equations for Dirac and Majorana neutrinos wave functions in matter we get the explicit expressions for the corresponding Green functions.4 pages, talk presented at HEP-2005, Lisbon, Portugal, July 21-27, 2005High Energy Physics - Phenomenologytext