public boolean remove(AccessibleRelation relation){
  if (relations == null) {
    return false;
  }
 else {
    return relations.removeElement(relation);
  }
}

public boolean remove ( AccessibleRelation relation ) { if ( relations == null ) { return false ; } else { return relations . removeElement ( relation ) ; } }
removes a relation from the current relation set . if the relation is not in the set , the relation set will be unchanged and the return value will be false . if the relation is in the relation set , it will be removed from the set and the return value will be true .
