Title:

On non-relativistic limits of Einstein (super)gravity

In this informal talk, I will point out some subtleties that arise when trying to take the non-relativistic limit of Einstein gravity, in a fashion that is fully diffeomorphism covariant. I will argue that this can be done by mimicking the Inonu-Wigner contraction procedure that allows one to obtain non-relativistic space-time symmetry algebras from relativistic ones. I will then show how this can be applied to suitable extensions of the Poincare algebra and how in three dimensions this leads to two different non-relativistic gravity theories. Finally, I will comment on supergravity generalizations of these theories and some potential applications.