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 [DEGKNW02], 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 Sch{\"u}zenberger
  graphs  of  finite inverse semigroups but also to visualize in the usual way
  the egg-box picture of a D-classe of a finite semigroup. Important note: The
  version  of  graphviz  to install should 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.