  
  [1X1 [33X[0;0YIntroduction[133X[101X
  
  [33X[0;0YGroupoids  are  mathematical  categories in which every arrow is invertible.
  The  [5XGpd[105X  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.[133X
  
  [33X[0;0YIt  was  used  by Emma Moore in her thesis [Moo01] to calculate normal forms
  for [13Xfree products with amalgamation[113X, and for [13XHNN-extensions[113X when the initial
  groups have rewriting systems.[133X
  
  [33X[0;0YThe current version is 1.42 for [5XGAP[105X 4.8, released on 15th February 2016.[133X
  
  [33X[0;0YThe  package may be obtained as a compressed tar file [11Xgpd-1.42.tar.gz[111X by ftp
  from one of the following sites:[133X
  
  [30X    [33X[0;6Yany                  [5XGAP[105X                 archive,                 e.g.
        [7Xhttp://www.gap-system.org/Packages/packages.html[107X;[133X
  
  [30X    [33X[0;6Ythe Bangor site: [7Xhttp://www.maths.bangor.ac.uk/chda/gap4/gpd/gpd.html[107X;[133X
  
  [30X    [33X[0;6Ythe package GitHub repository: [7Xhttps://github.com/gap-packages/gpd[107X.[133X
  
  [33X[0;0YThe  information  parameter  [10XInfoGpd[110X  takes  default  value [10X1[110X 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.[133X
  
  [33X[0;0YHelp is available in the usual way.[133X
  
  [4X[32X  Example  [32X[104X
    [4X[28X[128X[104X
    [4X[25Xgap>[125X [27XLoadPackage( "gpd" );[127X[104X
    [4X[28XLoading Gpd 1.41 for GAP 4.8 - Emma Moore and Chris Wensley ... [128X[104X
    [4X[28Xtrue[128X[104X
    [4X[28X[128X[104X
  [4X[32X[104X
  
  [33X[0;0YFor  version  1.05  the  package  was completely restructured, starting with
  [13Xmagmas  with  objects[113X  and  their mappings, and building up to groupoids via
  semigroups  with  objects  and  monoids  with objects. From version 1.07 the
  package  includes  some  functions  to  implement constructions contained in
  [AW10]. More functions will be released as soon as possible.[133X
  
  [33X[0;0YOnce the package is loaded, it is possible to check the correct installation
  by  running  the  test  suite  of the package with the command [10X ReadPackage(
  "gpd",  "tst/testall.g"  );  [110X  You  may reference this package by mentioning
  [BMPW02], [Moo01] and [AW10].[133X
  
