Cones and ping-pong in three dimensions

Gabriel Frieden, Félix Gélinas, Étienne Soucy

We study the hypergeometric group in ${\mathrm{GL}}_3(\mathbb{C})$ with parameters $\alpha =(\frac{1}{4},\frac{1}{2},\frac{3}{4})$ and $\beta =(0,0,0)$. We give a new proof that this group is…