 must be satisfied by any model of <code>Logical</code> are rigorously stated in the laws below.</p>
<h2><a class="anchor" id="autotoc_md129"></a>
Truth, falsity and logical equivalence</h2>
<p>A <code>Logical</code> <code>x</code> is said to be <em>true-valued</em>, or sometimes also just <em>true</em> as an abuse of notation, if </p><div class="fragment"><div class="line"><a class="code" href="group__group-_logical.html#gafd655d2222367131e7a63616e93dd080">if_</a>(x, <span class="keyword">true</span>, <spa