Integers, modular groups, and hyperbolic space. (English) Zbl 1451.11124
Conder, Marston D. E. (ed.) et al., Discrete geometry and symmetry. Dedicated to Károly Bezdek and Egon Schulte on the occasion of their 60th birthdays. Selected papers based on the presentations at the conference ‘Geometry and symmetry’, Veszprém, Hungary, June 29 – July 3, 2015. Cham: Springer. Springer Proc. Math. Stat. 234, 225-234 (2018).
