  
  [1X1 Introduction[0X
  
  Groupoids  are  mathematical  categories in which every arrow is invertible.
  The  [5XGpd[0m  package  provides functions for the computation with groupoids and
  their  morphisms;  for graphs of groups and graphs of groupoids. The package
  is far from complete, and development continues.
  
  It  was  used  by Emma Moore in her thesis [Moo01] to calculate normal forms
  for  Free  Products  with  Amalgamation,  and  for  HNN-extensions, when the
  initial groups have rewrite systems.
  
  [5XGpd[0m is implemented using [5XGAP[0m 4.4.
  
  The  information  parameter  [10XInfoGpd[0m  takes  default  value [10X1[0m which, for the
  benefit of new users, causes more messages to be printed out when operations
  fail. When raised to a higher value, additional information is printed out.
  
  Help is available in the usual way.
  
  [4X---------------------------  Example  ----------------------------[0X
    [4X[0X
    [4Xgap> LoadPackage( "gpd" );[0X
    [4X-----------------------------------------------------------[0X
    [4Xloading Gpd 1.05 for GAP 4.4 - Emma Moore and Chris Wensley[0X
    [4X-----------------------------------------------------------[0X
    [4Xtrue[0X
    [4X[0X
  [4X------------------------------------------------------------------[0X
  
  For version 1.05 the package has been completely restructured, starting with
  [13Xmagmas  with  objects[0m  and  their mappings, and building up to groupoids via
  semigroups  with  objects  and  monoids  with  objects.  This development is
  ongoing, and this manual does not mention all the available functions. A new
  version will be released as soon as possible.
  
  Once the package is loaded, it is possible to check the correct installation
  by  running  the  test suite of the package with the following command. (The
  test file itself is [11Xtst/gpd_manual.tst[0m.)
  
  [4X---------------------------  Example  ----------------------------[0X
    [4X[0X
    [4Xgap> ReadPackage( "gpd", "tst/testall.g" );[0X
    [4X+ Testing examples in Chapter 2 of the Gpd manual[0X
    [4X+ GAP4stones: 1250[0X
    [4X+ Testing examples in Chapter 3 of the Gpd manual[0X
    [4X+ GAP4stones: infinity[0X
    [4X+ Testing examples in Chapter 4 of the Gpd manual[0X
    [4X+ GAP4stones: 416[0X
    [4X+ Testing examples in Chapter 5 of the Gpd manual[0X
    [4X+ GAP4stones: 2500[0X
    [4X+ Testing examples in Chapter 6 of the Gpd manual[0X
    [4X+ GAP4stones: 28[0X
    [4X[0X
  [4X------------------------------------------------------------------[0X
  
  You may reference this package by mentioning [BMPW02] and [Moo01].
  
