Several "official" GAP packages are included, all of which are available from http://www.gap-system.org/Packages/packages.html. They are all released under the GPL with the following exception: GRAPE contains nauty (written by Brendon McKay).
A brief description of each package follows:
[http://www.math.wayne.edu/~kaym/research/ braid] is a GAP package for computing with braids, covering curves, and Hurwitz spaces.
[http://www.gap-system.org/Packages/ctbllib.html CTblLib] - The GAP Character Table Library
[http://www.gap-system.org/Packages/design.html DESIGN] is a package for classifying, partitioning and studying block designs.
[http://www.gap-system.org/Packages/factint.html FactInt] is a package providing routines for factoring integers, in particular:
- Pollard's p-1
- Williams' p+1
- Elliptic Curves Method (ECM)
- Continued Fraction Algorithm (CFRAC)
- Multiple Polynomial Quadratic Sieve (MPQS)
[http://www.gap-system.org/Packages/gapdoc.html GAPDoc] is a package containing a definition of a structure for GAP documentation, based on XML. It also contains conversion programs for producing text-, DVI-, PDF- or HTML-versions of such documents, with hyperlinks if possible.
[http://www.gap-system.org/Packages/grape.html GRAPE] ("GRaph Algorithms using PErmutation groups") is a package for computing with graphs and groups, and is primarily designed for constructing and analysing graphs related to groups, finite geometries, and designs.
[http://www.gap-system.org/Packages/hap.html HAP] ("Homological Algebra Programming") is a GAP package providing some functions for group cohomology computation.
[http://www.gap-system.org/Packages/laguna.html LAGUNA] ("Lie AlGebras and UNits of group Algebras") package provides functionality for calculation of the normalized unit group of the modular group algebra of the finite p-group and for investigation of Lie algebra associated with group algebras and other associative algebras.
[http://www.gap-system.org/Packages/sonata.html SONATA] ("System Of Nearrings And Their Applications") is a package which constructs finite nearrings and related objects.
[http://www.gap-system.org/Packages/toric.html TORIC] is a GAP package for computing with toric varieties.