# Diffeomorphisms of disks

## Location

Math 380-W

Thursday, November 14, 2019 4:30 PM

Alexander Kupers (Harvard)

Disks are among the simplest manifolds but their groups of diffeomorphisms can be very complicated. I will describe the geometric techniques that were used to understand these groups in low dimensions, their relationship 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 broad audience.