Dynamics on homogeneous spaces and new applications to number theory

Dmitry Kleinbock, Brandeis University

Nachdiplom Lectures at ETH, Zurich

Abstract: Dynamical systems on homogeneous spaces have been the subject of much attention recently, due to applications to number theory, geometric group theory, hyperbolic geometry etc. Interest in this area rose significantly after the seminal work of Margulis (the proof of the Oppenheim conjecture) and Ratner (Raghunathan’s conjectures) involving unipotent flows on homogeneous spaces. Later developments were considerably stimulated by applications to Diophantine approximation. I will survey basics of ergodic theory, then specialize to homogeneous dynamics, then highlight connections to number theory. The latter allow one to utilize certain properties of homogeneous flows, such as quantitative non-​divergence or effective equidistribution of unstable leaves, to prove new results in number theory.

Lecture 1: Introduction

Lecture 2: Homogeneous spaces, measure-preserving transformations

Lecture 3: Ergodic theorems, mixing, equidistribution

Lecture 4: Discrete subgroups and homogeneous spaces

Lecture 5: Latttices and finite volume quotients

Lecture 6: Ergodicity and mixing on homogeneous spaces

Lecture 7: Applications to number theory

Lecture 8: Exceptional orbits and number theory

Lecture 9: Shrinking targets and number theory

Lecture 10: Exponential mixing and shrinking targets

Lecture 11: Shrinking targets and Dirichlet improvability

Lecture 12: Other applications

Lecture 13: More applications and conclusion