{ "id": "math/9912070", "version": "v3", "published": "1999-12-09T08:54:49.000Z", "updated": "2000-09-14T21:19:22.000Z", "title": "On a compactification of the moduli space of the rational normal curves", "authors": [ "Paolo Cascini" ], "comment": "15 pages, ams-latex", "categories": [ "math.AG" ], "abstract": "For any odd $n$, we describe a smooth minimal (i.e. obtained by adding an irreducible hypersurface) compactification $\\tilde S_n$ of the quasi-projective homogeneous variety $S_{n}=PGL(n+1)/SL(2)$ that parameterizes the rational normal curves in $P^n$. We show that $\\tilde S_{n}$ is isomorphic to a component of the Maruyama scheme of the semi-stable sheaves on $P^n$ of rank $n$ and Chern polynomial $(1+t)^{n+2}$ and we compute its Betti numbers. In particular $\\tilde S_{3}$ is isomorphic to the variety of nets of quadrics defining twisted cubics, studied by G. Ellinsgrud, R. Piene and S. Str{\\o}mme (Space curves, Proc. Conf., LNM 1266).", "revisions": [ { "version": "v3", "updated": "2000-09-14T21:19:22.000Z" } ], "analyses": { "subjects": [ "14F05" ], "keywords": [ "rational normal curves", "moduli space", "compactification", "smooth minimal", "isomorphic" ], "note": { "typesetting": "LaTeX", "pages": 15, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "1999math.....12070C" } } }