Cohomology groups of finite groups on finite modules
Version 1.6.8
Released 2019-07-07
This project is maintained by The GAP Team
It may be used to perform certain cohomological calculations on a finite permutation group G. The following properties of G can be computed:
The p-part Mul_p of the Schur multiplier Mul of G, and a presentation of a covering extension of Mul_p by G, for a specified prime p;
The dimensions of the first and second cohomology groups of G acting on a finite dimensional KG-module M, where K is a field of prime order; and
Presentations of split and nonsplit extensions of M by G.
This package uses external binaries and currently works only under UNIX/LINUX systems.
To install the package go to the GAP directory pkg/cohomolo
(the
directory containing this README file) and call
./configure PATH
where PATH
is a path to the main GAP root directory; so normally you
would call
./configure ../..
and then call
make
to compile the binary.
If you installed GAP on several architectures, you must execute this
configure/make step for the cohomolo
package on each of the architectures
immediately after configuring GAP itself on this architecture.
Full information and documentation can be found in the manual, available
as PDF doc/manual.pdf
or as HTML htm/chapters.htm
, or on the package
homepage at
https://gap-packages.github.io/cohomolo/
Please submit bug reports and feature requests via our GitHub issue tracker:
https://github.com/gap-packages/cohomolo/issues
cohomolo 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 file LICENSE.
This package has been updated from the original GAP3 package
with minimal changes, so the user should find the interface unchanged.
In fact the only real changes are that the function InfoCohomology
has been
replaced by the Info
variable InfoCohomolo
, and the function
SplitExtension
has been renamed `SplitExtensionCHR, to avoid clashing
with an existing GAP function name. (Of course, it does more or less
the same thing as the GAP function!)