English

Thin actions on CAT(0) spaces

Metric Geometry 2022-11-29 v3

Abstract

We study groups of isometries of packed, geodesically complete, CAT(0)(0)-spaces for which the systole at every point is smaller than a universal constant depending only on the packing, deducing strong rigidity results. We show that if a space as above has some negative curvature behaviour then it cannot support a thin action: this generalizes the classical Margulis Lemma to a broader class of spaces.

Keywords

Cite

@article{arxiv.2210.01085,
  title  = {Thin actions on CAT(0) spaces},
  author = {Nicola Cavallucci and Andrea Sambusetti},
  journal= {arXiv preprint arXiv:2210.01085},
  year   = {2022}
}

Comments

v2: Correction of minor errors in Step 3 of the proof of Theorem 3.1. Remark 3.4 accordingly updated v3: Affiliations added

R2 v1 2026-06-28T02:42:31.811Z