We investigate finite sequences of hyperplanes in a pseudosphere. To each such sequence we associate a square symmetric matrix, the Gram matrix, which gives information about angle and incidence properties of the hyperplanes. We find when a given matrix is the Gram matrix of some sequence of hyperplanes, and when a sequence is determined up to isometry by its Gram matrix. We also consider subspaces of pseudospheres and projections onto them. This leads to an $n$-dimensional cosine rule for spherical and hyperbolic simplices. |

__Keywords__

__Math Review Classification__

Primary 15A21, 51M10

__Last Updated__

21/3/97

__Length__

21 pages

__Availability__

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