# Dodecahedral space

From Encyclopedia of Mathematics

The first example of a Poincaré space. Constructed by H. Poincaré in 1904. It is obtained by identifying the opposite faces of a dodecahedron after they have been rotated by an angle $\pi\over 5$ relative to each other. The dodecahedral space is a manifold of genus 2 with a Seifert fibration and is the only known Poincaré space with finite fundamental group. A dodecahedral space is the orbit space of the free action of a binary icosahedron group on the three-dimensional sphere.

#### References

[1] | H. Seifert, W. Threlfall, "Lehrbuch der Topologie" , Chelsea, reprint (1980) |

**How to Cite This Entry:**

Dodecahedral space.

*Encyclopedia of Mathematics.*URL: http://www.encyclopediaofmath.org/index.php?title=Dodecahedral_space&oldid=21691

This article was adapted from an original article by A.V. Chernavskii (originator), which appeared in Encyclopedia of Mathematics - ISBN 1402006098. See original article