2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/118488A strong primordial magnetic field can induce a relaxation of the present bound on the PQ-constant. We show that, considering the present limits on primordial magnetic fields, a value for the PQ-constant very close to the GUT scale is not excluded. This result naturally opens the possibility for the axion to be defined in the context of the GUT theories.4 pages, 1 figureAstrophysicstext