1 Introduction
  
  The  aim  of  this package is to turn  GAP  more user-friendly, at least for
  semigroup  theorists.  It  requires the usage of external programs as is the
  case of graphviz [DEG+02], a software for drawing graphs developed at AT & T
  Labs,  that can be obtained at http://www.graphviz.org/. It is used not only
  to draw right Cayley graphs of finite semigroups and Schüzenberger graphs of
  finite inverse semigroups but also to visualise in the usual way the egg-box
  picture  of a D-classe of a finite semigroup. Important note: The version of
  graphviz  to install must be greater or equal to 1.16. Tcl/Tk should also be
  available in order to run the graphical interfaces
  
  XAutomaton and XSemigroup
  used to specify automata and semigroups.
  
  Warning:  the  use  of XAutomaton and XSemigroup is intended only for simple
  examples. After its use one may have to start another GAP session.