# nLab Penrose-Hawking theorem

Contents

### Context

#### Gravity

gravity, supergravity

# Contents

## Idea

The Penrose-Hawking singularity theorems characterize spacetimes in the theory of Einstein-gravity (general relativity) which have “singularities”, points where the Riemann curvature is undefined (or would be undefined if these points were included in the spacetime manifold) such as appears notably in black hole spacetimes.

Hellman suggest this theorem as an example of noncomputable physics. See Frank for a response.

A related problem is that of the maximal Cauchy development for the Einstein equations. In this case, at least Zorn's lemma can be avoided.

## References

The original article:

• Stephen Hawking?, Roger Penrose, The Nature of Space and Time Princeton: Princeton University Press. ISBN 0-691-03791-4. (1996)

Review: