Skip navigation







FIELD Math:Topology
DATE May 27 (Wed), 2020
TIME 09:00-10:30
PLACE online
SPEAKER Tiozzo, Giulio
HOST Kim, Sang-hyun
INSTITUTE University of Toronto
TITLE Central limit theorems for counting measures in coarse negative curvature
ABSTRACT We establish general central limit theorems for an action of a group G on a hyperbolic space X with respect to the counting measure on a Cayley graph of G. In 2013, Chas, Li, and Maskit produced numerical experiments on random closed geodesics on a hyperbolic pair of pants. Namely, they drew uniformly at random conjugacy classes of a given word length, and considered the hyperbolic length of the corresponding closed geodesic on the pair of pants. Their experiments lead to the conjecture that the length of these closed geodesics satisfies a central limit theorem, and we proved this conjecture in 2018. In our new work, we remove the assumptions of properness and smoothness of the space, or cocompactness of the action, thus proving a general central limit theorem for group actions on hyperbolic spaces. We will see how our techniques replace the classical thermodynamic formalism and allow us to provide new applications, including to lengths of geodesics in geometrically finite manifolds and to intersection numbers with submanifolds. Joint work with I. Gekhtman and S. Taylor.
* This talk is a part of the online seminar series "Virtual Seminar on Geometry and Topology" using Zoom. To participate this seminar, please follow links at
  • list