arXiv · 1311.3866
The algebraic part of approach to groupoids started by S. Zakrzewski is presented.
Piotr Stachura. 2013-11-15. Short and biased introduction to groupoids. https://arxiv.org/abs/1311.3866
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We investigate reversible elements in the Picard modular group $\mathrm{PSL}(2,\mathbb{Z}[i])$. We show that reversibility coincides with strong reversibility for Kleinian groups, in particular for the Picard group. We classify reversible elements in the Picard group and characterize loxodromic reversible elements up to conjugacy. We prove that each such conjugacy class contains exactly eight special representatives. We also obtain asymptotic estimates for the number of reversible conjugacy classes with bounded trace.
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