pe of each variable is to be found in what is called the <em>context</em> or <em>typing context</em>.</p>
<ul>
<li>an <strong>application</strong> <code>[f e]</code> with <code>f</code> and <code>e</code> lambda-terms, informally <code>f</code> a function and <code>e</code> its argument</li>
</ul>
<p>If <code>f</code> is is type <code>(Π [x T] U)</code> and <code>e</code> is of type <code>T</code> then <code>[f e]</code> is of type <code>U</code> and realizes through beta-reduction the application of the f