  
  [1m[4m[31m1. Preface[0m
  
  Although  all  functionality  provided  by  this  package  is mathematically
  trivial,  the  author  thinks  that  having available a nice and easy-to-use
  implementation  of  residue  classes  as  sets which permits to form unions,
  intersections  and differences and which interacts smoothly with finite sets
  of  elements  w.r.t.  these operations is often useful. The functionality of
  this  package  is  used  in  a group theoretical context by the [1mRCWA[0m package
  written by the same author.
  
  I would be grateful for any bug reports, comments or suggestions.
  
