Freeness and $S$-arithmeticity of rational Möbius groups

A. S. Detinko, D. L. Flannery, A. Hulpke

We initiate a new, computational approach to a classical problem: certifying non-freeness of ($2$-generator, parabolic) Möbius subgroups of $\mathrm{SL}(2,\mathbb{Q})$. The main to…