{ "id": "0903.1029", "version": "v3", "published": "2009-03-05T16:45:51.000Z", "updated": "2011-01-21T16:22:39.000Z", "title": "Rational components of Hilbert schemes", "authors": [ "Paolo Lella", "Margherita Roggero" ], "comment": "27 pages; Theorem 4.7 and final example strengthened; final version: accepted for publication on Rendiconti del Seminario Matematico dell'Universit\\`a di Padova", "categories": [ "math.AG", "math.AC" ], "abstract": "The Gr\\\"obner stratum of a monomial ideal $\\id{j}$ is an affine variety that parametrizes the family of all ideals having $\\id{j}$ as initial ideal (with respect to a fixed term ordering). The Gr\\\"obner strata can be equipped in a natural way of a structure of homogeneous variety and are in a close connection with Hilbert schemes of subvarieties in the projective space $\\PP^n$. Using properties of the Gr\\\"obner strata we prove some sufficient conditions for the rationality of components of $\\hilb_{p(z)}^n$. We show for instance that all the smooth, irreducible components in $\\hilb_{p(z)}^n$ (or in its support) and the Reeves and Stillman component $H_{RS}$ are rational.", "revisions": [ { "version": "v3", "updated": "2011-01-21T16:22:39.000Z" } ], "analyses": { "subjects": [ "14C05" ], "keywords": [ "hilbert schemes", "rational components", "close connection", "affine variety", "initial ideal" ], "note": { "typesetting": "TeX", "pages": 27, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2009arXiv0903.1029L" } } }