                       README file for the XMod package 
                       ================================ 

Version 2.44, 13th November 2015 

Introduction 
------------
This package allows for computation with crossed modules; cat1-groups; morphisms of these structures; derivations of crossed modules and the corresponding sections of cat1-groups.
Experimental functions for crossed squares are now included. 
In October 2015 a new section on isoclinism of crossed modules was added. 

History
-------
Version 1 of ``XMod'' was accepted for GAP3R4P4 in December 1996.
The first version for GAP4 was XMod 2.001, released in April 2002. 
The latest Version, 2.44, was released on 13th November 2015 for GAP 4.7. 
A more detailed history is included as Chapter 11 of the manual, 
with minor changes detailed in the file CHANGES.

Distribution
-------------
The ``XMod'' package is distributed with the accepted GAP packages, see: 
     http://www.gap-system.org/Packages/xmod.html
It may also be obtained from the Bangor ftp pages for
Computational Higher-dimensional Discrete Algebra at: 
     http://pages.bangor.ac.uk/~mas023/chda/

Copyright
---------
The XMod package is Copyright {\copyright} Chris Wensley et al, 1997--2015. 
XMod 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 \URL{http://www.gnu.org/licenses/gpl.html}

Installation
------------
1) unpack `xmod-2.44.tar.gz' in the `pkg' subdirectory of the GAP root directory.
2) From within GAP load the package with:
gap> LoadPackage("XMod");
true
3) The file manual.pdf is in the `doc' subdirectory.

Contact
-------
If you have a question relating to XMod, encounter any problems, or have a suggestion for extending the package in any way, please 
 - email c.d.wensley@bangor.ac.uk 
 - or report an issue at https://github.com/gap-system/xmod/issues/new 
