>&nbsp;&nbsp;&nbsp;</td><td align="right">&sigma;&nbsp;=&nbsp;&tau; or =(&sigma;&nbsp;&tau;)</td><td>&nbsp;&nbsp;&nbsp;</td><td><span style="font-family: courier new,courier,monospace;">(=&nbsp;&sigma;&nbsp;&tau;)</span></td></tr>
<tr class="first"><td><span style="font-family: helvetica,arial,sans-serif; font-weight: bolder; font-size: small;">&nbsp;connectives</span></td><td>&nbsp;&nbsp;&nbsp;</td><td>&nbsp;</td><td>&nbsp;&nbsp;&nbsp;</td><td>&nbsp;</td></tr>
<tr class="middle"><td align="right">conjuncti