- Series
- Geometry Topology Seminar
- Time
- Monday, November 16, 2026 - 3:00pm for 1 hour (actually 50 minutes)
- Location
- Boyd 304 - University of Georgia, Athens
- Speaker
- Daniel Hartman – Duke University – https://sites.google.com/view/danielhhartman/home
- Organizer
- Eduardo Fernández
Please Note: This talk is part of the joint GT-UGA Topology seminar, and would take place in Athens.
Over the last 40 years, a considerable amount of progress has been made in studying the diffeomorphism group of the ball in all dimensions. It is now known that the space of diffeomorphisms of the n-ball that restrict to the identity on the boundary is not contractible for all dimensions n greater than or equal to four whereas in dimensions three and below, it is contractible. Over twenty years ago, Eliashberg asked the same question for the space of contactomorphisms/symplectomorphisms of the ball. To this end, Eliashberg and Mishachev showed it was true in dimension three while Gromov answered it affirmatively for dimension 4. In dimensions one and two, it follows from the corresponding result for diffeomorphisms. In my talk I will outline the proof that in all odd dimensions greater than or equal to 5, the contactomorphism group of the ball with the standard contact structure is not contractible.