README file for ``cohomolo'' package.

This package uses external binaries and works only under UNIX/LINUX systems.

It may be used to perform certain cohomological calculations on a finite
permutation group G.

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In fact the only real changes are that the function `InfoCohomology' has been
replaced by the `Info' variable `InfoCohomolo', and the function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!)

The following properties of G can be computed:

(i) 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;

(ii) 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

(iii) Presentations of split and nonsplit extensions of M by G.

To install the package go to the GAP directory `pkg/cohomolo' (the
directory containing this README file) and call

/bin/sh ./configure path

where path is a path to the main GAP root directory (so normally you would
call /bin/sh ./configure ../..).

afterwards 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.
