On the Gauss map of equivariant immersions in hyperbolic space
| Autor: | Emam, Christian El, Seppi, Andrea |
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| Rok vydání: | 2020 |
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| Zdroj: | Journal of Topology (2022) 15.1, 238-301 |
| Druh dokumentu: | Working Paper |
| Popis: | 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-K\"ahler 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 $\pi_1(M)$ 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. Comment: 55 pages, 12 figures. Minor improvements with respect to the previous version |
| Databáze: | arXiv |
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