epart from the usual boolean algebras because:</p><ol type="1">
<li>we do not require the elements representing truth and falsity to be unique</li>
<li>we do not enforce commutativity of the <code>and_</code> and <code>or_</code> operations</li>
<li>because we do not enforce commutativity, the identity laws become left-identity laws </li>
</ol>
</blockquote>
<h2><a class="anchor" id="autotoc_md132"></a>
Concrete models</h2>
<p><code><a class="el" href="structboost_1_1hana_1_1integral__constant.html" title="