/* IOA */
  public String format_ioa() {
    Quantify.IOAQuantification quant = VarInfo.get_ioa_quantify(var(), var());

    String result =
        quant.getQuantifierExp()
            + "("
            + quant.getMembershipRestriction(0)
            + " /\\ "
            + quant.getMembershipRestriction(1);

    // i \in X /\ j \in X => X[i] = X[j]

    result += ") => " + quant.getVarIndexedString(0) + " = " + quant.getVarIndexedString(1);
    return result + quant.getClosingExp();
  }