Nantes Université - Université Paris-Saclay

NANTES-ORSAY SEMINAR ON
SYMPLECTIC AND CONTACT GEOMETRY

Friday, 19 January 2024

 
The seminar will take place at the Université Paris-Saclay,
Building 307, 3rd floor, room 3L8.
Directions
 
Programme
 
10:30
Johanna Bimmermann (Bochum)
Capacities of disk cotangent bundles

Abstract: In general, little is known about symplectic capacities of open subsets of cotangent bundles. In this talk I will discuss methods to compute the Gromov width and the Hofer-Zehnder capacity of disk tangent bundles and demonstrate these methods for certain homogenous spaces (namely spheres and projective spaces). The key observation is that in these cases the disk bundle sits as complement of a divisor inside a hermitian symmetric space. This makes it possible to explicitly construct symplectic embeddings of balls for the lower bound and find non-vanishing Gromov-Witten invariants for the upper bound.
 
14:00
Julien Dardennes (Toulouse)
The coarse distance from dynamically convex to convex

Abstract: Chaidez and Edtmair have recently found the first examples of dynamically convex domains in ℝ4 that are not symplectomorphic to convex domains, answering a long-standing open question. In this talk, we present new examples of such domains without referring to Chaidez-Edtmair's criterion. We also show that these domains are arbitrarily far from the set of symplectically convex domains in ℝ4 with respect to the coarse symplectic Banach-Mazur distance by using an explicit numerical criterion for symplectic non-convexity (joint work with J. Gutt, V. Ramos and J. Zhang).
 
 
15:30
Discussions
Université de Nantes UPSAY
 
Vincent Colin Frédéric Bourgeois