{ "id": "math/0505266", "version": "v4", "published": "2005-05-12T15:41:06.000Z", "updated": "2006-09-19T15:04:04.000Z", "title": "Singular curves on a K3 surface and linear series on their normalizations", "authors": [ "Flaminio Flamini", "Andreas Leopold Knutsen", "Gianluca Pacienza" ], "comment": "20 pages, remarks of the referee are added, to be published on International Journal of Mathematics", "categories": [ "math.AG" ], "abstract": "In this paper, we study the Brill-Noether theory of the normalizations of singular, irreducible curves on a $K3$ surface. We introduce a {\\em singular} Brill-Noether number $\\rho_{sing}$ and show that if the Picard group of the K3 surface is ${\\mathbb Z} [L]$, there are no $g^r_d$'s on the normalizations of irreducible curves in $|L|$, provided that $\\rho_{sing} <0$. We give examples showing the sharpness of this result. We then focus on the case of {\\em hyperelliptic normalizations}, and classify linear systems $|L|$ containing irreducible nodal curves with hyperelliptic normalizations, for $\\rho_{sing}<0$, without any assumption on its Picard group.", "revisions": [ { "version": "v4", "updated": "2006-09-19T15:04:04.000Z" } ], "analyses": { "subjects": [ "14H10", "14H51", "14J28", "14J60" ], "keywords": [ "k3 surface", "linear series", "singular curves", "picard group", "hyperelliptic normalizations" ], "note": { "typesetting": "TeX", "pages": 20, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2005math......5266F" } } }