Abstract

Let [Formula: see text] be a compact connected Riemann surface of genus at least two. The Abel–Jacobi map [Formula: see text] is an embedding if [Formula: see text] is less than the gonality of [Formula: see text]. We investigate the curvature of the pull-back, by [Formula: see text], of the flat metric on [Formula: see text]. In particular, we show that when [Formula: see text], the curvature is strictly negative everywhere if [Formula: see text] is not hyperelliptic, and when [Formula: see text] is hyperelliptic, the curvature is nonpositive with vanishing exactly on the points of [Formula: see text] fixed by the hyperelliptic involution.

Highlights

  • Let X be a compact connected Riemann surface of genus g, with g ≥ 2

  • The gonality of X is defined to be the smallest integer γX such that there is a nonconstant holomorphic map from X to CP1 of degree γX

  • Picd(X) is equipped with a flat Kahler form, which we will denote by ω0

Read more

Summary

Introduction

Let X be a compact connected Riemann surface of genus g, with g ≥ 2. Picd(X) is equipped with a flat Kahler form, which we will denote by ω0. Φ∗ω0 is a Kahler form on Symd(X), whenever d < γX. Our aim here is to study the curvature of this Kahler form φ∗ω0 on Symd(X). Consider the g–dimensional vector space H0(X, KX ) consisting of holomorphic oneforms on X. It is equipped with a natural Hermitian structure. We prove that the holomorphic Hermitian vector bundle ρ∗V −→ Symd(X) is isomorphic to the holomorphic cotangent bundle ΩSymd(X) equipped with the Hermitian structure given by φ∗ω0 (Theorem 3.1). Since the curvature of the holomorphic Hermitian vector bundle V −→ G is standard, Theorem 3.1 gives a description of the curvature of φ∗ω0 in terms of ρ.

Gonality and flat metric
Mapping to a Grassmannian
Full Text
Paper version not known

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.