IAS Lecture: When Classical Billiards Meet Symplectic Geometry and Modern Dynamics
Guest Lecturer: Professor Sergei Tabachnikov, Pennsylvania State University, USA
Geometry and Dynamics Seminar: A Tale of Four Billiards – Focusing on the Nonconventional Ones
Tel Aviv University's Institute of Advanced Studies is pleased to welcome Professor Sergei Tabachnikov, Professor of Mathematics at Pennsylvania State University. He is visiting Tel Aviv University as part of the IAS Distinguished Scholars series 2025–2026 and will speak at the Geometry and Dynamics Seminar of the TAU School of Mathematical Sciences.
In his talk, “A Tale of Four Billiards: Focusing on the Nonconventional Ones,” Professor Sergei Tabachnikov will explore how variations on classical billiard systems open new windows into modern geometry and dynamics.
Starting from the traditional Birkhoff billiard, whose periodic orbits form polygons of extremal perimeter, he will show how replacing “perimeter” with “area” and “inscribed” with “circumscribed” gives rise to three other intriguing billiard-like systems. Two of these extend naturally to symplectic spaces, leading to symplectic inner and outer billiards—systems with rich geometric and dynamical behavior.
Professor Tabachnikov will discuss periodic orbits and large-scale trajectories in these models, and reveal how they connect to Minkowski billiards, a central topic in contemporary symplectic topology.
When: January 14, 2026 | 14:00
Where: Schreiber Building, Room 309
Light refreshments will be served before the lecture.
The lecture will be conducted in English and is open to the public.
The Institute of Advanced Studies at Tel Aviv University promotes academic excellence by hosting leading scholars from diverse fields worldwide.
