2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/67033We consider projective varieties with degenerate Gauss image whose focal hypersurfaces are non-reduced schemes. Examples of this situation are provided by the secant varieties of Severi and Scorza varieties. The Severi varieties are moreover characterized by a uniqueness property.9 pages, to be published in Pacific Journal of MathematicsAlgebraic GeometryDifferential Geometry14N20, 14J30text