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.