# XMod

Crossed Modules and Cat1-Groups

Version 2.64

This project is maintained by Christopher D. Wensley

# The GAP 4 package ‘XMod’

## 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.

In October 2015 a new section on isoclinism of crossed modules was added.

Experimental functions for crossed squares and cat2-groups are now included.

## Distribution

‘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.

## Installation

• Unpack xmod-<version_number>.tar.gz in the pkg subdirectory of the GAP root directory.
• From within GAP load the package with: