</td><td>&nbsp;&nbsp;&nbsp;</td><td>&nbsp;</td></tr>
<tr class="middle"><td align="right">&nbsp;set&nbsp;element</td><td>&nbsp;&nbsp;&nbsp;</td><td align="right"><span style="font-style: italic;">x</span>&nbsp;&isin;&nbsp;<span style="font-style: italic;">X</span> or <span style="font-style: italic;">X</span>(<span style="font-style: italic;">x</span>)</td><td>&nbsp;&nbsp;&nbsp;</td><td><span style="font-family: courier new,courier,monospace;">(X&nbsp;x)</span></td></tr>
<tr class="middle"><td align="right"