English

J{\o}rgensen Number and Arithmeticity

Geometric Topology 2013-01-29 v1 Group Theory

Abstract

A J{\o}rgensen group is a non-elementary Kleinian group that can be generated by two elements for which equality holds in J{\o}rgensen's Inequality. This paper shows that the only torsion-free J{\o}rgensen group is the figure-eight knot group, identifies all non-cocompact arithmetic J{\o}rgensen groups, and establishes a characterization of cocompact arithmetic J{\o}rgensen groups. The paper also defines and computes the J{\o}rgensen number of several non-cocompact Kleinian groups including some two-bridge knot and link groups.

Keywords

Cite

@article{arxiv.0905.1318,
  title  = {J{\o}rgensen Number and Arithmeticity},
  author = {Jason Callahan},
  journal= {arXiv preprint arXiv:0905.1318},
  year   = {2013}
}

Comments

27 pages, 2 figures