English

A simultaneous Abels-Margulis-Soifer lemma

Group Theory 2025-08-12 v1

Abstract

The Abels-Margulis-Soifer lemma states that if a semigroup Γ\Gamma acts strongly irreducibly by linear transformations on a finite-dimensional real vector space, then any element of Γ\Gamma can be multiplied by an element of some fixed finite subset of Γ\Gamma so that it becomes proximal (i.e. it acts on the corresponding projective space with an attracting fixed point and a repelling projective hyperplane) and even uniformly proximal (i.e. the distance between the attracting fixed point and the repelling projective hyperplane is uniformly bounded from below and the contraction towards the attracting fixed point is uniformly strong). We prove a version of this lemma simultaneously for linear representations of a semigroup Γ\Gamma, acting on the corresponding projective spaces, and for representations of Γ\Gamma to isometry groups of (not necessarily proper) Gromov hyperbolic metric spaces, acting on the corresponding Gromov boundaries.

Keywords

Cite

@article{arxiv.2508.08111,
  title  = {A simultaneous Abels-Margulis-Soifer lemma},
  author = {Fanny Kassel and Rafael Potrie},
  journal= {arXiv preprint arXiv:2508.08111},
  year   = {2025}
}

Comments

23 pages

R2 v1 2026-07-01T04:44:34.779Z