class="language-clojure">(lambda [x T] e) ≡ (λ [x T] e)

(lambda [x1 x2 ... xN T] e)
≡ (λ [x1 T] (λ [x2 T] ... (λ [xN T] e) ... ))
</code></pre>
<ul>
<li>a <strong>product-abstraction</strong> (a.k.a. <em>Π-type</em>) <code>(Π [x T] e)</code> (with <code>x</code>, <code>T</code>, <code>e</code> as in the lambda case)</li>
</ul>
<p>The <em>Π-types</em> are probably the most distinguishing feature of type theories such as <em>λC</em>. These simply are the <em>types</em> of the lambda-abstractions.