Triple

Target class: type D Petrov spacetime
Context triple: [Kerr–Newman black hole, instanceOf, type D Petrov spacetime]

• A. Lorentzian manifold
  A Lorentzian manifold is a smooth manifold equipped with a metric tensor of signature \((-+\cdots+)\) (or its variants) that models spacetime in general relativity by distinguishing timelike, spacelike, and null directions.
• B. Eddington–Finkelstein coordinate system
  The Eddington–Finkelstein coordinate system is a reformulation of the Schwarzschild spacetime using null (lightlike) coordinates that smoothly extend across the event horizon, eliminating the coordinate singularity present in standard Schwarzschild coordinates.
• C. pseudo-Riemannian manifold chosen
  A pseudo-Riemannian manifold is a smooth manifold equipped with a nondegenerate, symmetric metric tensor of arbitrary signature that allows measurement of lengths and angles, including those with indefinite sign as in spacetime geometry.
• D. Penrose diagram
  A Penrose diagram is a spacetime diagram used in general relativity that compactifies infinite regions to finite size, allowing the global causal structure of a spacetime to be visualized.
• E. spacetime coordinate chart
  A spacetime coordinate chart is a mapping that assigns a unique set of numerical coordinates to each event in a region of spacetime, providing a local reference frame for describing physical phenomena.
• F. None of above.