# nLab homotopy sphere

Contents

### Context

#### Spheres

n-sphere

low dimensional n-spheres

# Contents

## Idea

A homotopy sphere is a topological space which need not be homeomorphic to an n-sphere, but which has the same homotopy type as an $n$-sphere.

## References

• Laurent Siebenmann, Topological Poincaré conjecture in dimension 4 (the work of M. H. Freedman) (pdf)

Last revised on December 1, 2019 at 14:12:35. See the history of this page for a list of all contributions to it.