A GAP 4 package for
Computing with Radicals, Injectors
Schunck classes and Projectors
of finite soluble groups

Burkhard Höfling, e-mail: replacing ö by oe
GAP (requires at least Version 4.5)
Operating System:
Current version:
crisp-1.4.6.tar.bz2 in .tar.bz2 format
Other formats available from the CRISP page on the main GAP server.
Home page:
CRISP manual
Available in HTML format Adobe Acrobat PDF format
Development version
Accessible via GitHub repository
Bugs and suggestions
GitHub issue tracker or by e-mail to the author.


The GAP package CRISP provides algorithms for computing subgroups of finite soluble groups related to group classes. In particular, it allows to compute F-radicals and F-injectors for Fitting classes (and Fitting sets) F, F-residuals for formations F, and X-projectors for Schunck classes X. In order to carry out these computations, the group classes F and Xmust be given by an algorithm which decides membership in the group class.

Moreover, CRISP contains algorithms for the computation of normal subgroups invariant under a prescribed set of automorphisms and belonging to a given group class. This includes an improved method to compute the set of all normal subgroups of a finite soluble group, its characteristic subgroups, and the socle and p-socles for given primes p.

Author: Burkhard Höfling
Last modified: 15/12/2022