arXiv · 1307.6580
We exhibit an example of a finitely presented monoid that is congruence-free and simple but not bisimple.
Alan J. Cain, Victor Maltcev. 2013-07-24. A simple non-bisimple congruence-free finitely presented monoid. https://doi.org/10.1007/s00233-014-9607-y
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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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