The Hypersphere reference article from the English Wikipedia on 24-Jul-2004
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Hypersphere

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A hypersphere is a higher-dimensional analogue of a sphere. A hypersphere of radius r in n-dimensional Euclidean space consists of all points at distance r from a given fixed point (the centre of the hypersphere).

The "volume" it encloses is

where Γ is the gamma function.

The "surface area" of this hypersphere is

Table of contents
1 Terminology
2 See also
3 External link

Terminology

Confusingly, geometers and topologists have different names for the above object in n-dimensions.

Geometrical terminology

Following Coxeter, geometers call the above object an n-sphere. Hence, an ordinary sphere in three dimensions would be called a "3-sphere".

Topological terminology

Topologists call the above object an (n−1)-manifold or an (n−1)-sphere. Hence, the special case of an ordinary sphere in three dimensions would be called a "2-sphere".

See also

External link