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 | | The other spacetime, coming from a hyperboloid in the flat 5d spacetime with metric of signature (+ + - - -), is also maximally symmetric, and its isometry group is the 10-dimensional group SO(2,3). |
 | | With the hyperboloid definition of dS, its topology is RxS^3. |
 | | As it turns out, everyone's right, according to his or her own definition of "de Sitter space" and "spatially finite." When cosmologists talk about de Sitter space, we slice it up into constant-time hypersurfaces that are spatially flat and infinite. |
| www.math.niu.edu /~rusin/known-math/00_incoming/universe (1835 words) |
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