Group Actions and Dynamics Seminar

During the Fall 2024 semester, RTG / Group Actions and Dynamics seminar meets in room B325 Van Vleck on Mondays from 2:25pm - 3:15pm. To sign up for the mailing list send an email from your wisc.edu address to dynamics+join@g-groups.wisc.edu. For more information, contact Paul Apisa, Marissa Loving, Caglar Uyanik, Chenxi Wu or Andy Zimmer.

Fall 2024

date	speaker	title	host(s)
September 9	Max Lahn (Michigan)	TBA	Uyanik and Zimmer
September 16	Ben Lowe (Chicago)	TBA	Al Assal
September 23	Harrison Bray (George Mason)	A 0-1 law for horoball packings of coarsely hyperbolic metric spaces and applications to cusp excursion	Zimmer
September 30	Eliot Bongiovanni (Rice)	TBA	Uyanik
October 7	Francis Bonahon (USC/Michigan State)	TBA	Loving
October 21	Dongryul Kim (Yale)	TBA	Uyanik
October 28	Matthew Durham (UC Riverside)	TBA	Loving
November 4	Caglar Uyanik (UW)	Cannon-Thurston maps, random walks, and rigidity	local

Fall Abstracts

Harrison Bray

On the cusp of the 100 year anniversary, Khinchin's theorem implies a strong 0-1 law for the real line; namely, the set of real numbers within distance q^{-2-\epsilon} of infinitely many rationals p/q is Lebesgue measure 0 for \epsilon>0, and full measure for \epsilon=0. In these lectures, I will present an analogous result for horoball packings in Gromov hyperbolic metric spaces. As an application, we prove a logarithm law; that is, we prove asymptotics for the depth in the packing of a typical geodesic. This is joint work with Giulio Tiozzo.

Caglar Uyanik

Cannon and Thurston showed that a hyperbolic 3-manifold that fibers over the circle gives rise to a sphere-filling curve. The universal cover of the fiber surface is quasi-isometric to the hyperbolic plane, whose boundary is a circle, and the universal cover of the 3-manifold is 3-dimensional hyperbolic space, whose boundary is the 2-sphere. Cannon and Thurston showed that the inclusion map between the universal covers extends to a continuous map between their boundaries, whose image is dense. In particular, any measure on the circle pushes forward to a measure on the 2-sphere using this map. We compare several natural measures coming from this construction.

Spring 2025

date	speaker	title	host(s)
January 27	Ben Stucky (Beloit)	TBA	semi-local
April 21	Mladen Bestvina (Utah)	Distinguished Lecture Series	Uyanik
April 28	Inanc Baykur (UMass)	TBA	Uyanik

Archive of past Dynamics seminars

2023-2024 Dynamics_Seminar_2023-2024

2022-2023 Dynamics_Seminar_2022-2023

2021-2022 Dynamics_Seminar_2021-2022

2020-2021 Dynamics_Seminar_2020-2021