2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/73497The Hilbert scheme of projective 3-folds of codimension 3 or more that are linear scrolls over the projective plane or over a smooth quadric surface or that are quadric or cubic fibrations over the projective line is studied. All known such threefolds of degree from 7 to 11 are shown to correspond to smooth points of an irreducible component of their Hilbert scheme, whose dimension is computed. A relationship with the locus of good determinantal subschemes is investigatedTo appear in Communications in AlgebraAlgebraic Geometry14J30; 14M07; 14N25; 14N30text