The 2m <= r property of spherically symmetric static spacetimes
Abstract
We prove that all spherically symmetric static spacetimes which are both regular at r=0 and satisfying the single energy condition rho + pr + pt >= 0 cannot contain any black hole region (equivalently, they must satisfy 2m/r <= 1 everywhere). This result holds even when the spacetime is allowed to contain a finite number of matching hypersurfaces. This theorem generalizes a result by Baumgarte and Rendall when the matter contents of the space-time is a perfect fluid and also complements their results in the general non-isotropic case.
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