Topological obstruction for Anosov representations into PO(p, q)
Abstract
We establish new restrictions on the virtual cohomological dimension of word hyperbolic groups admitting Anosov representations into PO(p, q) (p > q ≥ 2) or the exceptional Lie group G2'. Our main result states that, if Pk is the parabolic subgroup of PO(p, q) stabilizing an isotropic k-plane in ℝp, q, a group admitting a {P1,Pq}-Anosov representation into PO(p, q) has virtual cohomological dimension strictly less than p. As a result, a Hp, q−1-convex cocompact subgroup of PO(p, q) cannot act properly discontinuously and cocompactly on Hp, q−1. The main theorem also implies that a group admitting a Pα-Anosov representation into the exceptional Lie group G2' has virtual cohomological dimension strictly less than $4$, where α is a short restricted root of G2'. As an application, we prove that the homogeneous space G2'/ SU(2, 1) does not admit any compact quotient.
Related
- Non-Hitchin Borel Anosov representations from surface groups to SL3kℝ
- On the Topological Transitivity of Interval Extensions of Anosov Diffeomorphisms
- Boundary of Anosov coaffine representations
- Topological Expansivity and Shadowing for Anosov Diffeomorphisms
- Flux Vacua, Asymptotic Periods, and Relatively Anosov Representations
BibTeX
@misc{li2026topological,
title = {{Topological obstruction for Anosov representations into $\operatornamePO(p, q)$}},
author = {Kewei Li},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.20197},
eprint = {2610.20197},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.20197},
}
RIS
TY - UNPB
TI - Topological obstruction for Anosov representations into PO(p, q)
AU - Kewei Li
PY - 2026
DA - 2026/10/14
PB - arXiv
DO - 10.48550/arxiv.2610.20197
UR - https://arxiv.org/abs/2610.20197
AB - We establish new restrictions on the virtual cohomological dimension of word hyperbolic groups admitting Anosov representations into PO(p, q) (p > q ≥ 2) or the exceptional Lie group G_2'. Our main result states that, if P_k is the parabolic subgroup of PO(p, q) stabilizing an isotropic k-plane in ℝ^p, q, a group admitting a {P_1,P_q}-Anosov representation into PO(p, q) has virtual cohomological dimension strictly less than p. As a result, a H^p, q−1-convex cocompact subgroup of PO(p, q) cannot act properly discontinuously and cocompactly on H^p, q−1. The main theorem also implies that a group admitting a P_α-Anosov representation into the exceptional Lie group G_2' has virtual cohomological dimension strictly less than $4$, where α is a short restricted root of G_2'. As an application, we prove that the homogeneous space G_2'/ SU(2, 1) does not admit any compact quotient.
ER -