Search arXivSearch

arXiv · alg-geom/9607005

The orbifold fundamental group of Persson-Noether-Horikawa surfaces

Abstract

The Noether-Horikawa surfaces are the minimal surfaces S with K^2=2p_g-4. For 8 | K^2 they belong to two families of respective type C and N (connected, resp. non connected branch locus for the canonical map). For 16 | K^2 the two types are homeomorphic. Ulf Persson constructed surfaces of type N with a maximally singular canonical model X, whose topology encodes information on the differentiable structure of S. A similar analysis was done by the first author for type C. In this paper we study the genus 2 fibration on X and, in particular, our main result is (X^# being the nonsingular locus of X) π_1(X^#)= Z_4 x Z_4 if 8 | K^2 but 16 does not | K^2 π_1(X^#)= Z_4 x Z_2 if 16 | K^2.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Fabrizio Catanese, Sandro Manfredini. 1996-07-04. The orbifold fundamental group of Persson-Noether-Horikawa surfaces. https://arxiv.org/abs/alg-geom/9607005

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

Deforming Calabi-Yau Threefolds

This paper first generalises the Bogomolov-Tian-Todorov unobstructedness theorem to the case of Calabi-Yau threefolds with canonical singularities. The deformation space of such a Calabi-Yau threefold is no longer smooth, but the general principle is that the obstructions to deforming such a threefold are precisely the obstructions to deforming the singularities of the threefold. Secondly, these results are applied to smoothing singular Calabi-Yau threefolds with crepant resolutions. Any such Calabi-Yau threefold with isolated complete intersection singularities which are not ordinary double points is smoothable. A Calabi-Yau threefold with non-complete intersection isolated singularities is proved to be smoothable under much stronger hypotheses.

alg-geom

Classification of Varieties with Canonical Curve Section via Gaussian maps on Canonical Curves

Let $C \subset P^{g-1}$ be a smooth canonical curve of genus $g \geq 3$. The purpose of this article is to further develop a method to classify varieties having $C$ as their curve section, using Gaussian map computations. In a previous article a careful analysis of the degeneration to the cone over the hyperplane section was made for _prime_ Fano threefolds, that is Fano threefolds whose Picard group is generated by the hyperplane bundle. In this article we extend this method and classify Fano threefolds of higher index (which still have Picard number one). We are also able to classify Mukai varieties, i.e. varieties of dimension four or more with canonical curve sections.

alg-geom