# nLab Penrose diagram

This entry is about the Roger Penrose‘s diagrams reflecting causal structure of spacetimes in general relativity. For the Penrose notation for tensors in linear algebra see at string diagram.

### Context

#### Gravity

gravity, supergravity

# Contents

## Idea

In the theory of gravity (general relativity) the Penrose diagram of a given spacetime is a 2-dimensional depiction (time running vertically and a single spatial distance coordinate running horizontally) of its causal structure, reflecting the projected image of the spacetime under a conformal transformation which makes events at timelike/spacelike/lightlike infinity of the spacetime appear at respective boundary points of its Penrose diagram.

## References

Due to Roger Penrose.