The joint maximal drift of Euclidean isometries
报告人：Jairo Bochi (Pennsylvania State University, US)
时间：2026-10-13 22:00-23:00 (Beijing Time)
地点：Zoom
Abstract: Given a finite collection of isometries of a non-compact metric space, we want to compose them in such a way that trajectories tend to infinity as fast as possible. We would like to compute this maximal drift and describe the shift-invariant measures that attain it. This is naturally a problem in Ergodic Optimization. If the ambient space is the hyperbolic plane, the maximal drift is directly related to a joint spectral radius, and it's widely believed that the corresponding maximizing measures are typically supported on periodic orbits. In this talk, we will focus on isometries of the Euclidean plane. In this setting, periodic optimizers are no longer typical. Nevertheless, we are able to describe drift-maximizing measures explicitly for a subset of the parameter space with positive Lebesgue measure. A key step in our analysis is a reduction to a problem of standard ergodic optimization over a partially hyperbolic skew-product system. Joint work with Pablo Lessa (Udelar, Uruguay).
Zoom Meeting ID: 832 0847 3832
Passcode: Ergodic
