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<!-- ##  abstract.xml      ResClasses documentation       Stefan Kohl  ## -->
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  &ResClasses; is a package for &GAP; 4 which provides a fully-featured
  and easy-to-use implementation of set-theoretic unions of residue classes
  of the integers and of a few other rings. <P/>

  The class of sets which &ResClasses; can deal with includes the open and
  the closed sets in the topology on the respective ring which is induced by
  taking the set of all residue classes as a basis, as far as the usual
  restrictions imposed by the finiteness of computing resources permit this.
  <P/>

  The package further provides slightly more specialized functionality
  for unions of residue classes with distinguished representatives and
  signed moduli. <P/>

  The &ResClasses; package is used in a group theoretical context by the
  &RCWA; package&nbsp;<Cite Key="RCWA"/>.

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