2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/198535We propose a theory of flavour based on abelian horizontal gauge symmetries and modular invariances. We construct explicit supergravity models where the scale of the horizontal $U(1)$ symmetry breaking is fixed by the Green-Schwarz mechanism for anomaly cancellation. The supersymmetric spectrum is obtained in terms of the $U(1)$ charges which are determined by the Yukawa matrices.30 pages, LaTeX, no figuresHigh Energy Physics - Phenomenologytext