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<!-- manual.xml IdRel documentation Chris Wensley -->
<!-- & Anne Heyworth -->
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<!-- $Id: manual.xml,v 2.05 Exp $ -->
<!DOCTYPE Book SYSTEM "gapdoc.dtd"
[<!ENTITY idrel "<Package>IdRel</Package>">] >
<Book Name="IdRel">
<TitlePage>
<Title>&idrel;</Title>
<Subtitle>A package for Identities among Relators</Subtitle>
<Version>Version 2.05</Version>
<Author> Anne Heyworth
<Email>anne.heyworth@googlemail.com</Email>
</Author>
<Author> Chris Wensley
<Email>c.d.wensley@bangor.ac.uk</Email>
<Homepage>http://www.bangor.ac.uk/~mas023/</Homepage>
<Address>
School of Computer Science, Bangor University,<Br/>
Dean Street, Bangor, Gwynedd, LL57 1UT, U.K.
</Address>
</Author>
<Date>November 2008</Date>
<Abstract>
The &idrel; package was originally implemented in 1999,
using the &GAP; 3 language,
when the first author was studying for a Ph.D. in Bangor.
<P/>
This package is designed to compute a minimal set of generators
for the module of the identities among relators of a group presentation.
It does this using
<List>
<Item>
rewriting and logged rewriting: a self-contained implementation
of the Knuth-Bendix process using the monoid presentation
associated to the group presentation;
</Item>
<Item>
monoid polynomials: an implementation of the monoid ring;
</Item>
<Item>
module polynomials: an implementation of the right module
over this monoid generated by the relators.
</Item>
<Item>
Y-sequences: used as a <E>rewriting</E> way of representing
elements of a free crossed module
(products of conjugates of group relators and inverse relators).
</Item>
</List>
<P/>
Bug reports, suggestions and comments are, of course, welcome.
Please contact the second author at
<Email>c.d.wensley@bangor.ac.uk</Email>.
</Abstract>
<Copyright>
©right; 2005-2008 Anne Heyworth and Chris Wensley <P/>
</Copyright>
<Acknowledgements>
This <Package>idrel</Package> package is released under the
GNU General Public License (GPL).
This file is part of <Package>idrel</Package>, though as documentation
it is released under the
GNU Free Documentation License
(see <URL>http://www.gnu.org/licenses/licenses.html#FDL</URL>).
<P/>
<Package>idrel</Package> 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.
<P/>
<Package>idrel</Package> is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the GNU General Public License for more details.
<P/>
You should have received a copy of the GNU General Public License
along with <Package>idrel</Package>; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
<P/>
For more details, see
<URL>http://www.fsf.org/licenses/gpl.html</URL>.
<P/>
This documentation was prepared with the <Package>GAPDoc</Package>
package of Frank L\"ubeck and Max Neunh\"offer.
</Acknowledgements>
</TitlePage>
<TableOfContents/>
<Body>
<#Include SYSTEM "intro.xml">
<#Include SYSTEM "rws.xml">
<#Include SYSTEM "logrws.xml">
<#Include SYSTEM "monpoly.xml">
<#Include SYSTEM "modpoly.xml">
</Body>
<Bibliography Databases="manual"/>
<TheIndex/>
</Book>
