Black holes in higher dimensions.
Blow-up for solutions of hyperbolic PDE and spacetime singularities
An important question in mathematical relativity theory is that of the nature of spacetime singularities. The equations of general relativity, the Einstein equations, are essentially hyperbolic in nature and the study of spacetime singularities is naturally related to blow-up phenomena for nonlinear hyperbolic systems. These connections are explained and recent progress in applying the theory of hyperbolic equations in this field is presented. A direction which has turned out to be fruitful is that...
Boundary conditions for the Einstein-Christoffel formulation of Einstein's equations.
Braided Groups
Brief comments on the Note «Qualche osservazione sulle forze centrali in Relatività Ristretta» of Luigi Stazi
The central «pseudopotentials» yielding, in relativistic mechanics, closed (bounded) orbits for any given energy are derived by inspection (of the algebraic form of the hamiltonian).
By Magri's theorem, self-dual gravity is completely integrable.