tr>
<tr><td align="left"><br>I</td></tr>
<tr><td><a href="Interval2.html#VALinv_i">inv_i</a> [<a href="Interval2.html">Interval2</a>]</td>
<td><div class="info">
Interval reciprocal <b>(optimal)</b>
</div>
</td></tr>
<tr><td><a href="Interval1.html#VALinv_i">inv_i</a> [<a href="Interval1.html">Interval1</a>]</td>
<td><div class="info">
Interval reciprocal
</div>
</td></tr>
<tr><td><a href="Interval2.html#VALis_empty">is_empty</a> [<a href="Interval2.html">Interval2</a>]</td>
<td><div class="info">
Tests if 