Skip to content

Actions on CAT(-1) spaces with critical exponent less than 1

Beibei Liu, Shi Wang

math.GTarXiv:2608.18906

Abstract

We show that for a discrete isometry subgroup acting on a proper CAT(-1) space X, if the critical exponent is less than 1, then the critical exponent equals the Hausdorff dimension of the entire limit set. Consequently, the limit set must be a Cantor set. As an application, we prove that any finitely generated, torsion-free discrete subgroup in Isom(X) with critical exponent less than one must be geometrically finite and free. This answers a question of Kapovich.

Create a lesson