Triple

Target class: conformal diagram
Context triple: [Reissner–Nordström Penrose diagram, instanceOf, conformal diagram]

• A. conformal spacetime diagram
  A conformal spacetime diagram is a rescaled representation of spacetime in which light rays always travel at 45 degrees, preserving causal structure while compactifying infinite regions into a finite, manageable picture.
• B. Penrose diagram chosen
  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.
• C. 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.
• D. 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.
• E. 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.
• F. None of above.