On the Gauss map of equivariant immersions in hyperbolic space

Fuente: arXiv
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Main Authors: Emam, Christian El, Seppi, Andrea
Format: Preprint
Published: 2020
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author Emam, Christian El
Seppi, Andrea
author_facet Emam, Christian El
Seppi, Andrea
contents Given an oriented immersed hypersurface in hyperbolic space $\mathbb{H}^{n+1}$, its Gauss map is defined with values in the space of oriented geodesics of $\mathbb{H}^{n+1}$, which is endowed with a natural para-Kähler structure. In this paper we address the question of whether an immersion $G$ of the universal cover of an $n$-manifold $M$, equivariant for some group representation of $π_1(M)$ in $\mathrm{Isom}(\mathbb{H}^{n+1})$, is the Gauss map of an equivariant immersion in $\mathbb{H}^{n+1}$. We fully answer this question for immersions with principal curvatures in $(-1,1)$: while the only local obstructions are the conditions that $G$ is Lagrangian and Riemannian, the global obstruction is more subtle, and we provide two characterizations, the first in terms of the Maslov class, and the second (for $M$ compact) in terms of the action of the group of compactly supported Hamiltonian symplectomorphisms.
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id arxiv_https___arxiv_org_abs_2008_07390
institution arXiv
publishDate 2020
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spellingShingle On the Gauss map of equivariant immersions in hyperbolic space
Emam, Christian El
Seppi, Andrea
Differential Geometry
Geometric Topology
Symplectic Geometry
Given an oriented immersed hypersurface in hyperbolic space $\mathbb{H}^{n+1}$, its Gauss map is defined with values in the space of oriented geodesics of $\mathbb{H}^{n+1}$, which is endowed with a natural para-Kähler structure. In this paper we address the question of whether an immersion $G$ of the universal cover of an $n$-manifold $M$, equivariant for some group representation of $π_1(M)$ in $\mathrm{Isom}(\mathbb{H}^{n+1})$, is the Gauss map of an equivariant immersion in $\mathbb{H}^{n+1}$. We fully answer this question for immersions with principal curvatures in $(-1,1)$: while the only local obstructions are the conditions that $G$ is Lagrangian and Riemannian, the global obstruction is more subtle, and we provide two characterizations, the first in terms of the Maslov class, and the second (for $M$ compact) in terms of the action of the group of compactly supported Hamiltonian symplectomorphisms.
title On the Gauss map of equivariant immersions in hyperbolic space
topic Differential Geometry
Geometric Topology
Symplectic Geometry
url https://arxiv.org/abs/2008.07390