gap-congruence - 1.2.4-1 main

GAP is a system for computational discrete algebra, with particular emphasis
on Computational Group Theory. GAP provides a programming language, a library
of thousands of functions implementing algebraic algorithms written in the GAP
language as well as large data libraries of algebraic objects. GAP is used in
research and teaching for studying groups and their representations, rings,
vector spaces, algebras, combinatorial structures, and more.
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The Congruence package provides functions to construct several types of
canonical congruence subgroups in SL_2(Z), and also intersections of a finite
number of such subgroups. Furthermore, it implements the algorithm for
generating Farey symbols for congruence subgroups and using them to produce a
system of independent generators for these subgroups