Stefan Nemirovski (Bochum and Moscow) will talk in the geometry seminar at 2pm on 14/03/2023 in the Salles des Profs (9t floor of building NO). Stefan’s title is “Legendrian submanifolds and causality” and his abstract is below.

*Roger Penrose observed that the celestial spheres of points in a reasonable spacetime are Legendrian submanifolds in its contact manifold of light rays. It turns out that several notions of causality theory can be defined on spaces of Legendrian submanifolds in a way compatible with the Penrose correspondence. The talk will discuss those notions in the context of global rigidity (and occasionally flexibility) of contact manifolds.*