Axial distances in discrete Möbius groups.

Gehring, F W; Martin, G J · Proc Natl Acad Sci U S A · 1992

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Abstract

We describe here new lower bounds for the trace of the commutator of a discrete two-generator group of Möbius transformations. These results lead to sharp estimates for the distance between the axes of elliptics in a discrete group and hence to new bounds for the volume of hyperbolic manifolds and orbifolds that will be discussed elsewhere.