  
  [1X1. Introduction[0X
  
  This manual describes the [5XIdRel[0X (version 2.03) [5XGAP[0X package for computing the
  identities  among  relations of a group presentation using rewriting, logged
  rewriting, monoid polynomials, module polynomials and Y-sequences.
  
  The  theoretical background for these computations is contained in Brown and
  Huebschumann  [BH82],  Brown  and  Razak  Salleh  [BS99]  and is surveyed in
  [Hey99].
  
  [5XIdRel[0X  is  primarily  designed  for  the  computation  of  a  minimal set of
  generators  for  the  module of identities among relations. It also contains
  functions  which compute logged rewrite systems for group presentations (and
  complete  them  where possible), functions for operations involving elements
  of  monoid rings and functions for operations with elements of right modules
  over  monoid  rings.  The  Y-sequences  are  used  as  a  [13Xrewriting[0X  way  of
  representing  elements  of  a free crossed module (products of conjugates of
  group  relators  and  inverse  relators). The package is written entirely in
  [5XGAP[0X4, and requires no compilation.
  
  The  package  is  loaded  into [5XGAP[0X with the [10XLoadPackage[0X command, and on-line
  help is available in the usual way.
  
  [4X---------------------------  Example  ----------------------------[0X
    [4X[0X
    [4Xgap> LoadPackage( "idrel" ); [0X
    [4Xgap> ?idrel[0X
    [4X[0X
  [4X------------------------------------------------------------------[0X
  
  A  pdf  version of the [5XIdRel[0X manual is available in the [11Xdoc[0X directory of the
  home  directory  of  [5XIdRel[0X.  The information parameter [10XInfoIdRel[0X has default
  value  [10X0[0X.  When  raised to a higher value, additional information is printed
  out.  [5XIdRel[0X was originally developed in 1999 using [5XGAP[0X3, partially supported
  by  a  University of Wales Research Assistantship for the first author, Anne
  Heyworth. If you use [5XIdRel[0X to solve a problem then please send a short email
  to  the  second  author, to whom bug reports, suggestions and other comments
  should  also be sent. You may reference the package by mentioning [HW03] and
  [Hey99].
  
