{ "id": "math/0107100", "version": "v1", "published": "2001-07-13T08:06:55.000Z", "updated": "2001-07-13T08:06:55.000Z", "title": "The classification of double planes of general type with $K^2=8$ and $p_g=0$", "authors": [ "Rita Pardini" ], "comment": "LaTeX2e, 23 pages", "categories": [ "math.AG" ], "abstract": "We study minimal {\\em double planes} of general type with $K^2=8$ and $p_g=0$, namely pairs $(S,\\sigma)$, where $S$ is a minimal complex algebraic surface of general type with $K^2=8$ and $p_g=0$ and $\\sigma$ is an automorphism of $S$ of order 2 such that the quotient $S/\\sigma$ is a rational surface. We prove that $S$ is a free quotient $(F\\times C)/G$, where $C$ is a curve, $F$ is an hyperelliptic curve, $G$ is a finite group that acts faithfully on $F$ and $C$, and $\\sigma$ is induced by the automorphism $\\tau\\times Id$ of $F\\times C$, $\\tau$ being the hyperelliptic involution of $F$. We describe all the $F$, $C$ and $G$ that occur: in this way we obtain 5 families of surfaces with $p_g=0$ and $K^2=8$, of which we believe only one was previously known. Using our classification we are able to give an alternative description of these surfaces as double covers of the plane, thus recovering a construction proposed by Du Val. In addition we study the geometry of the subset of the moduli space of surfaces of general type with $p_g=0$ and $K^2=8$ that admit a double plane structure.", "revisions": [ { "version": "v1", "updated": "2001-07-13T08:06:55.000Z" } ], "analyses": { "subjects": [ "14J29" ], "keywords": [ "general type", "double plane", "classification", "minimal complex algebraic surface", "study minimal" ], "note": { "typesetting": "LaTeX", "pages": 23, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2001math......7100P" } } }