/*
  * @see
  * org.jakstab.analysis.LatticeElement#lessOrEqual(org.jakstab.analysis.
  * LatticeElement)
  */
 @Override
 public boolean lessOrEqual(LatticeElement l) {
   if (l.isTop() || this.isBot()) return true;
   if (isTop() || l.isBot()) return false;
   SubstitutionElement other = (SubstitutionElement) l;
   if (expression.equals(other.getExpression())) return true;
   return false;
 }
 /*
  * @see
  * org.jakstab.analysis.AbstractValue#join(org.jakstab.analysis.LatticeElement
  * )
  */
 @Override
 public SubstitutionElement join(LatticeElement l) {
   if (l.isBot()) return this;
   SubstitutionElement other = (SubstitutionElement) l;
   if (this.isBot()) return other;
   if (expression.equals(other.getExpression())) return this;
   return TOP;
 }