One theorem about the existence of these entities was challenged by considering a rotating plane of dust by Shapiro and Teukolsky, and two-dimensional versions of them are called domain walls.
The "fuzzball theory" posits that a bunch of strings replace these entities in one location. One theorem about the existence of these entities was challenged by considering a rotating plane of dust by Shapiro and Teukolsky, and two-dimensional versions of them are called domain walls. One of these can be shown to exist by showing that the derivative of the reciprocal of the expansion with respect to proper time is greater than or equal to one-third using Raychaudhuri's equation. They can occur in a ring in the Kerr solution, and one of these things can be found by noting the points at which both the metric tensor and the determinant of the Riemann tensor (*) blow up. Both spacelike and timelike ones have geodesic incompleteness according to one set of theorems. One of these arises when considering the Robertson-Walker metric backwards in time, while another occurs at r equals zero of the Schwarzchild solution. Naked ones don't exist according to the cosmic censorship hypothesis. For 10 points, name these things supposedly found within black holes, regions of space which have zero volume and infinite density.
The "fuzzball theory" posits that a bunch of strings replace these entities in one location.
singularity