On computing finite index subgroups of PSL(2,Z)
Number Theory
2025-05-13 v1 Group Theory
Abstract
We present a method to compute finite index subgroups of . Our strategy follows Kulkarni's ideas, the main contribution being a recursive method to compute bivalent trees and their automorphism group. As a concrete application, we compute all subgroups of index up to 20. We then use this database to produce tables with several arithmetical properties.
Keywords
Cite
@article{arxiv.2307.01826,
title = {On computing finite index subgroups of PSL(2,Z)},
author = {Nicolás Mayorga Uruburu and Ariel Pacetti and Leandro Vendramin},
journal= {arXiv preprint arXiv:2307.01826},
year = {2025}
}
Comments
27 pages, several figures