Goursatʹs problem and the holographic principle Original Research Article

The whole idea of holography as put forward by Gerard ʹt Hooft assumes that data on a boundary determine physics in the volume. This corresponds to a Dirichlet problem for Euclidean signature, or to a Goursat (characteristic) problem in the Lorentzian setting. Is this last aspect of the problem that is explored here for Ricci flat spaces with vanishing cosmological constant.