2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/166769Consider the smooth quadric Q_6 in P^7. The middle homology group H_6(Q_6,Z) is two-dimensional with a basis given by two classes of linear subspaces. We classify all threefolds of bidegree (1,p) inside Q_6.14 pages; added Propositions 3.6 and 4.4 in version 2Algebraic GeometryDifferential Geometrytext