2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/166055To every covering of curves, we associate several varieties having the same field of moduli and same fields of definition. We deduce examples of curves having Q (the field of rationals) as field of moduli, that admit models over any completion of Q but no model over Q.Number TheoryAlgebraic Geometry12Y05; 12F10; 11R37text