# Contents

## Definition

The plane is the Cartesian space $\mathbb{R}^2$. This is naturally a topological space, a manifold, and a smooth manifold.

This is the stage of Euclidean geometry.

## References

For discussion of the plane via axioms for the points and lines in it (synthetic geometry) see the references at Euclidean geometry.

Revised on March 17, 2017 01:49:41 by Urs Schreiber (192.41.133.235)