Diffeomorphisms of DiscsConfirmed

by Alexander Kupers (University of Toronto Scarborough)

Tuesday Feb 17, 2026, 9:30 AM → 11:00 AM America/Toronto

PI/4-405 - Bob Room (Perimeter Institute for Theoretical Physics)

Discs are among the simplest manifolds, but their groups of diffeomorphisms can be very complicated. I will describe the techniques from geometry, topology, and dynamics that were used to understand these groups in low dimensions, the relationship of these groups to stable homotopy theory and number theory in high dimensions, and recent breakthroughs in understanding their rational homotopy type. This talk will be aimed at a broader audience.