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
directory containing this README file) and call
PATH is a path to the main GAP root directory; so normally you
and then call
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
doc/manual.pdf or as HTML
htm/chapters.htm, or on the package
Please submit bug reports and feature requests via our GitHub issue tracker:
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InfoCohomology has been
replaced by the
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!)