Scalar invariants of the radiating Kerr–Newman metric: A simple application of GRTensor

GRTensor is an interactive PC‐based program for tensor analysis primarily of interest for teaching and research in general relativity. It uses either maplev or mathematica as its algebraic engine. In this paper we use GRTensor to evaluate the Ricci and Weyl invariants for the radiating Kerr–Newman metric. This includes, as a special case, all nonvanishing invariants of the Kerr metric—the archetypical black hole solution in general relativity.