English

$\mathbb{H}^{p,q}$-convex cocompactness and higher higher Teichm\"uller spaces

Geometric Topology 2025-10-06 v7 Group Theory

Abstract

For any integers p2p\geq 2 and q1q\geq 1, let Hp,q\mathbb{H}^{p,q} be the pseudo-Riemannian hyperbolic space of signature (p,q)(p,q). We prove that if Γ\Gamma is the fundamental group of a closed aspherical pp-manifold, then the set of representations of Γ\Gamma to PO(p,q+1)\mathrm{PO}(p,q+1) which are convex cocompact in Hp,q\mathbb{H}^{p,q} is a union of connected components of Hom(Γ,PO(p,q+1))\mathrm{Hom}(\Gamma,\mathrm{PO}(p,q+1)). More generally, we show that if Γ\Gamma is any finitely generated group with no infinite nilpotent normal subgroups and with virtual cohomological dimension pp, then the set of injective and discrete representations of Γ\Gamma to PO(p,q+1)\mathrm{PO}(p,q+1) preserving a non-degenerate non-positive (p1)(p-1)-sphere in the boundary of Hp,q\mathbb{H}^{p,q} is a union of connected components of Hom(Γ,PO(p,q+1))\mathrm{Hom}(\Gamma,\mathrm{PO}(p,q+1)). This gives new examples of higher-dimensional higher-rank Teichm\"uller spaces.

Keywords

Cite

@article{arxiv.2305.15031,
  title  = {$\mathbb{H}^{p,q}$-convex cocompactness and higher higher Teichm\"uller spaces},
  author = {Jonas Beyrer and Fanny Kassel},
  journal= {arXiv preprint arXiv:2305.15031},
  year   = {2025}
}

Comments

75 pages, 1 figure. To appear in Geom. Funct. Anal