Proof of the Caratheodory Conjecture

Fuente: arXiv
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Autori principali: Guilfoyle, Brendan, Klingenberg, Wilhelm
Natura: Preprint
Pubblicazione: 2008
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author Guilfoyle, Brendan
Klingenberg, Wilhelm
author_facet Guilfoyle, Brendan
Klingenberg, Wilhelm
contents A well-known conjecture of Caratheodory states that the number of umbilic points on a closed convex surface in ${\mathbb E}^3$ must be greater than one. In this paper we prove this for $C^{3+α}$-smooth surfaces. The Conjecture is first reformulated in terms of complex points on a Lagrangian surface in $TS^2$, viewed as the space of oriented geodesics in ${\mathbb E}^3$. Here complex and Lagrangian refer to the canonical neutral Kaehler structure on $TS^2$. We then prove that the existence of a closed convex surface with only one umbilic point implies the existence of a totally real Lagrangian hemisphere in $TS^2$, to which it is not possible to attach the edge of a holomorphic disc. The main step in the proof is to establish the existence of a holomorphic disc with edge contained on any given totally real Lagrangian hemisphere. To construct the holomorphic disc we utilize mean curvature flow with respect to the neutral metric. Long-time existence of this flow is proven by a priori estimates and we show that the flowing disc is asymptotically holomorphic. Existence of a holomorphic disc is then deduced from Schauder estimates.
format Preprint
id arxiv_https___arxiv_org_abs_0808_0851
institution arXiv
publishDate 2008
record_format arxiv
spellingShingle Proof of the Caratheodory Conjecture
Guilfoyle, Brendan
Klingenberg, Wilhelm
Differential Geometry
Analysis of PDEs
Symplectic Geometry
53A05
A well-known conjecture of Caratheodory states that the number of umbilic points on a closed convex surface in ${\mathbb E}^3$ must be greater than one. In this paper we prove this for $C^{3+α}$-smooth surfaces. The Conjecture is first reformulated in terms of complex points on a Lagrangian surface in $TS^2$, viewed as the space of oriented geodesics in ${\mathbb E}^3$. Here complex and Lagrangian refer to the canonical neutral Kaehler structure on $TS^2$. We then prove that the existence of a closed convex surface with only one umbilic point implies the existence of a totally real Lagrangian hemisphere in $TS^2$, to which it is not possible to attach the edge of a holomorphic disc. The main step in the proof is to establish the existence of a holomorphic disc with edge contained on any given totally real Lagrangian hemisphere. To construct the holomorphic disc we utilize mean curvature flow with respect to the neutral metric. Long-time existence of this flow is proven by a priori estimates and we show that the flowing disc is asymptotically holomorphic. Existence of a holomorphic disc is then deduced from Schauder estimates.
title Proof of the Caratheodory Conjecture
topic Differential Geometry
Analysis of PDEs
Symplectic Geometry
53A05
url https://arxiv.org/abs/0808.0851