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We describe a family of 4–dimensional hyperbolic orbifolds, constructed by deforming
an infinite volume orbifold obtained from the ideal, hyperbolic 24–cell by removing
two walls. This family provides an infinite number of infinitesimally rigid, infinite
covolume, geometrically finite discrete subgroups of Isom(H4). It also leads to finite
covolume Coxeter groups which are the homomorphic image of the group of
reflections in the hyperbolic 24–cell. The examples are constructed very explicitly,
both from an algebraic and a geometric point of view. The method used can be
viewed as a 4–dimensional, but infinite volume, analog of 3–dimensional hyperbolic
Dehn filling.
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