Finite-index subgroups of (P)SL(2,Integers)

Version 2.0.0
Released 2022-07-14

This project is maintained by Luca Leon Junk, Gabriela Weitze-Schmithüsen

GAP Package ModularGroup

This package provides a collection of algorithms for computing with finite-index subgroups of (P)SL(2,Z).

The current version of this package is version 2.0.0, released on 2022-07-14.


This package requires GAP version 4.5.3

The following other GAP packages are needed:

The following additional GAP packages are not required, but suggested:


Luca Leon Junk, Gabriela Weitze-Schmithüsen.


Please, cite this package as

[JW22] Junk, L. L. and Weitze-Schmithüsen, G., ModularGroup, Finite-index subgroups of (P)SL(2,Integers), Version 2.0.0 (2022)
(GAP package),

You can get more info by typing Cite("ModularGroup"); in the gap prompt.


For bug reports, feature requests and suggestions, please use the issue tracker.