2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/110354Let M and N be two representations of an extended Dynkin quiver such that the orbit O_N of N is contained in the orbit closure \bar{O_M} and has codimension two. We show that the pointed variety $(\bar{O_M},N)$ is smoothly equivalent to a simple surface singularity of type A_n, or to the cone over a rational normal curve.16 pagesAlgebraic GeometryRepresentation Theory14B05 (Primary) 14L30, 16G20 (Secondary)text