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#              Matrix Group and G-Module library
#                     Version 1.0
#
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We announce the availability by anonymous FTP of a matrix group and G-module
library for use with GAP 3.3 (and later versions). A version of this
code will be distributed as a package with GAP 3.4.

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This library provides functions which may be used to construct
and investigate the structure of matrix groups defined over finite
fields. These functions permit the user to construct certain types
of matrix groups and G-modules; to test whether a G-module is
irreducible or absolutely irreducible; to decide whether a group
is imprimitive or has certain decomposition with respect to a
normal subgroup; and to select random elements with certain properties.

The code was developed as part of the on-going project to "recognise"
the Aschbacher categories of matrix groups defined over finite fields.

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The interested reader is referred to the following papers for details of
the algorithms used. Preprints of these papers are distributed with the
package.

Derek F. Holt and Sarah Rees, ``Testing modules for irreducibility'',
J. Austral. Math. Soc. Ser. A, 57, 1994.

Derek F. Holt, Charles R. Leedham-Green, E.A. O'Brien and Sarah Rees,
``Computing matrix group decompositions with respect to a normal
subgroup'', submitted to London Math. Soc., 1994.

Derek F. Holt, Charles R. Leedham-Green, E.A. O'Brien and Sarah Rees,
``Primitivity testing for matrix groups'', submitted to London
Math. Soc., 1994.

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The Unix tar file, matrix.v1-0.tar.Z, of the program may be
fetched by anonymous ftp from

pell.anu.edu.au (IP number 150.203.33.4)

It is in the pub/matrix directory

The file can be uncompressed using the command

uncompress matrix.v1-0.tar.Z

Then the file can be unpacked using the command

tar -xvf matrix.v1-0.tar

This will create a directory called matrix and needs
about 1 MB of free disk space.

Please read the README file in the matrix directory for
all necessary details.

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The library was developed by:

Derek Holt, Mathematics Institute, Warwick
dfh@maths.warwick.ac.uk

Charles Leedham-Green, School of Mathematical Studies, QMW
C.R.Leedham-Green@qmw.ac.uk

Eamonn O'Brien, School of Mathematical Sciences, ANU
Eamonn.OBrien@maths.anu.edu.au

Sarah Rees, Department of Mathematics and Statistics, Newcastle
Sarah.Rees@newcastle.ac.uk

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Feedback, queries, and bug reports are welcome.

Eamonn O'Brien
School of Mathematical Sciences
Australian National University
Canberra, 0200

April 1994