Arr;&nbsp;&psi; or &hArr;(&phi;&nbsp;&psi;)</td><td>&nbsp;&nbsp;&nbsp;</td><td><span style="font-family: courier new,courier,monospace;">(iff&nbsp;P&nbsp;Q)</span>&nbsp;or&nbsp;<span style="font-family: courier new,courier,monospace;">(<=>&nbsp;P&nbsp;Q)</span></td></tr>
<tr class="middle"><td align="right">negation</td><td>&nbsp;&nbsp;&nbsp;</td><td align="right">&not;&nbsp;&phi; or &not;(&phi;)</td><td>&nbsp;&nbsp;&nbsp;</td><td><span style="font-family: courier new,courier,monospace;">(not&nbsp;P)</span>