From: itsme213@... (you CAN teach an old dog ...)
Date: 2003-06-07T13:09:10+09:00
Subject: Relation class

Does anyone know of a Relation class with methods such as
  domain
  range
  add
  remove
  image
  inverse_image
  compose
  inverse_compose
  inverse
  override
 
etc.?

Thanks.