2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/61163In this paper we focus on the problem of computing the number of moduli of the so called Severi varieties (denoted by V(|D|, δ)), which parametrize universal families of irreducible, δ-nodal curves in a complete linear system |D|, on a smooth projective surface S of general type. We determine geometrical and numerical conditions on D and numerical conditions on δensuring that such number coincides with dim(V(|D|, δ). As related facts, we also determines some sharp results concerning the geometry of some Severi varieties.Latex2e, 27 pagesAlgebraic Geometry14J29 (Primary), 14H10 (Secondary)text