A characterization of double covers of curves in terms of the ample cone of second symmetric product

2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/160471We investigate the nef cone spanned by the diagonal and the fibre classes of second symmetric product of a curve of genus $g$. This 2-dimensional nef cone gives a characterization of double covers of curves of genus $\le \frac{g-1}{8}$. This is a generalization of a result by Debarre.13 pages, to appear in J. Pure App. AlgebraAlgebraic GeometryA characterization of double covers of curves in terms of the ample cone of second symmetric producttext