Diffeomorphic to the 3 sphere.
- Unitary group | 82, 155, 3
- Important Lie groups | 0, 978, 14
- Lie group | 233, 2k, 24
- Differential geometry | 12, 2k, 25
- Geometry | 0, 2k, 34
- Mathematics | 17, 13k, 336
- Ciro Santilli's Homepage | 262, 182k, 3k
- 3-sphere | 11