&Congruence;

Congruence subgroups of SL_2(&ZZ;)

Version &VERSION;
Ann Dooms andooms@vub.ac.be http://homepages.vub.ac.be/˜andooms

            Department of Mathematics, Vrije Universiteit Brussel

            Pleinlaan 2, Brussels, B-1050 Belgium

Eric Jespers efjesper@vub.ac.be http://homepages.vub.ac.be/˜efjesper

            Department of Mathematics, Vrije Universiteit Brussel

            Pleinlaan 2, Brussels, B-1050 Belgium

Olexandr Konovalov obk1@st-andrews.ac.uk https://olexandr-konovalov.github.io/

            School of Computer Science

            University of St Andrews

            Jack Cole Building, North Haugh,

            St Andrews, Fife, KY16 9SX, Scotland

Helena Verrill verrill@math.lsu.edu http://www.math.lsu.edu/˜verrill/

            Department of Mathematics

            Louisiana State University

            Baton Rouge, Louisiana, 70803-4918

            USA

&RELEASEDATE;
&Congruence; package The &GAP; package &Congruence; provides functionality to work with congruence subgroups of SL_2(&ZZ;).
©right; 2006-&RELEASEYEAR; by Ann Dooms, Eric Jespers, Olexandr Konovalov and Helena Verrill.

&Congruence; is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. For details, see the FSF's own site https://www.gnu.org/licenses/gpl.html.

If you obtained &Congruence;, we would be grateful for a short notification sent to one of the authors.

If you publish a result which was partially obtained with the usage of &Congruence;, please cite it in the following form:

A. Dooms, E. Jespers, O. Konovalov and H. Verrill. Congruence --- Congruence subgroups of SL_2(&ZZ;), Version &VERSION;; &RELEASEYEAR; (https://gap-packages.github.io/congruence/).
We are very grateful to Mong-Lung Lang, Chong-Hai Lim and Ser Peow Tan for their comments provided while implementing algorithms from and , and to Francqui Stichting (Belgium) for the support of the third author.
<#Include SYSTEM "intro.xml"> <#Include SYSTEM "cong.xml"> <#Include SYSTEM "farey.xml"> <#Include SYSTEM "gens.xml"> <#Include SYSTEM "service.xml">