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Almost strict domination and anti-de Sitter 3-manifolds

Nathaniel Sagman

Abstract

We define a condition called almost strict domination for pairs of representations $ρ_1:π_1(S_{g,n})\to \textrm{PSL}(2,\mathbb{R})$, $ρ_2:π_1(S_{g,n})\to G$, where $G$ is the isometry group of a Hadamard manifold $(X,ν)$, and prove it holds if and only if one can find a $(ρ_1,ρ_2)$-equivariant spacelike maximal surface in a certain pseudo-Riemannian manifold, unique up to fixing some parameters. The proof amounts to setting up and solving an interesting variational problem that involves infinite energy harmonic maps. Adapting a construction of Tholozan, we construct all such representations and parametrize the deformation space. When $(X,ν)=(\mathbb{H},σ)$, an almost strictly dominating pair is equivalent to the data of an anti-de Sitter 3-manifold with specific properties. The results on maximal surfaces provide a parametrization of the deformation space of such $3$-manifolds as a union of components in a $\textrm{PSL}(2,\mathbb{R})\times \textrm{PSL}(2,\mathbb{R})$ relative representation variety.

Almost strict domination and anti-de Sitter 3-manifolds

Abstract

We define a condition called almost strict domination for pairs of representations , , where is the isometry group of a Hadamard manifold , and prove it holds if and only if one can find a -equivariant spacelike maximal surface in a certain pseudo-Riemannian manifold, unique up to fixing some parameters. The proof amounts to setting up and solving an interesting variational problem that involves infinite energy harmonic maps. Adapting a construction of Tholozan, we construct all such representations and parametrize the deformation space. When , an almost strictly dominating pair is equivalent to the data of an anti-de Sitter 3-manifold with specific properties. The results on maximal surfaces provide a parametrization of the deformation space of such -manifolds as a union of components in a relative representation variety.

Paper Structure

This paper contains 37 sections, 33 theorems, 162 equations.

Key Result

Theorem 1.3

A finitely generated discrete group $\Gamma_{\rho_1,\rho_2}\subset \textrm{PSL}(2,\mathbb{R})\times \textrm{PSL}(2,\mathbb{R})$ of the form (form) acts properly discontinuously and without torsion on $\textrm{AdS}^3$ if and only if $\rho_1$ is Fuchsian and strictly dominates $\rho_2$, up to intercha

Theorems & Definitions (79)

  • Remark 1.1
  • Definition 1.2
  • Theorem 1.3: Guéritaud-Kassel, Theorem 1.8 in GK
  • Theorem 1.4: Deroin-Tholozan, Theorem A in DT
  • Theorem 1.5: Tholozan, Theorem 1 in T
  • Definition 1.6
  • Proposition 1.7
  • Definition 1.8
  • Proposition 1.9
  • Remark 1.10
  • ...and 69 more