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Bibliographic Details
Main Author: Mettler, Thomas
Format: Preprint
Published: 2015
Subjects:
Online Access:https://arxiv.org/abs/1510.01043
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author Mettler, Thomas
author_facet Mettler, Thomas
contents We introduce a new functional $\mathcal{E}_{\mathfrak{p}}$ on the space of conformal structures on an oriented projective manifold $(M,\mathfrak{p})$. The nonnegative quantity $\mathcal{E}_{\mathfrak{p}}([g])$ measures how much $\mathfrak{p}$ deviates from being defined by a $[g]$-conformal connection. In the case of a projective surface $(Σ,\mathfrak{p})$, we canonically construct an indefinite Kähler--Einstein structure $(h_{\mathfrak{p}},Ω_{\mathfrak{p}})$ on the total space $Y$ of a fibre bundle over $Σ$ and show that a conformal structure $[g]$ is a critical point for $\mathcal{E}_{\mathfrak{p}}$ if and only if a certain lift $\widetilde{[g]} : (Σ,[g]) \to (Y,h_{\mathfrak{p}})$ is weakly conformal. In fact, in the compact case $\mathcal{E}_{\mathfrak{p}}([g])$ is -- up to a topological constant -- just the Dirichlet energy of $\widetilde{[g]}$. As an application, we prove a novel characterisation of properly convex projective structures among all flat projective structures. As a by-product, we obtain a Gauss--Bonnet type identity for oriented projective surfaces.
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publishDate 2015
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spellingShingle Extremal conformal structures on projective surfaces
Mettler, Thomas
Differential Geometry
Analysis of PDEs
Geometric Topology
We introduce a new functional $\mathcal{E}_{\mathfrak{p}}$ on the space of conformal structures on an oriented projective manifold $(M,\mathfrak{p})$. The nonnegative quantity $\mathcal{E}_{\mathfrak{p}}([g])$ measures how much $\mathfrak{p}$ deviates from being defined by a $[g]$-conformal connection. In the case of a projective surface $(Σ,\mathfrak{p})$, we canonically construct an indefinite Kähler--Einstein structure $(h_{\mathfrak{p}},Ω_{\mathfrak{p}})$ on the total space $Y$ of a fibre bundle over $Σ$ and show that a conformal structure $[g]$ is a critical point for $\mathcal{E}_{\mathfrak{p}}$ if and only if a certain lift $\widetilde{[g]} : (Σ,[g]) \to (Y,h_{\mathfrak{p}})$ is weakly conformal. In fact, in the compact case $\mathcal{E}_{\mathfrak{p}}([g])$ is -- up to a topological constant -- just the Dirichlet energy of $\widetilde{[g]}$. As an application, we prove a novel characterisation of properly convex projective structures among all flat projective structures. As a by-product, we obtain a Gauss--Bonnet type identity for oriented projective surfaces.
title Extremal conformal structures on projective surfaces
topic Differential Geometry
Analysis of PDEs
Geometric Topology
url https://arxiv.org/abs/1510.01043