 e2] e3]
(e1 e2 e3 e4) ≡ [[[e1 e2] e3] e4]
;; etc.
</code></pre>
<ul>
<li>a <strong>reference</strong> <code>(r e1 ... eN)</code> with <code>r</code> the name of a <strong>defined term</strong> and <code>e1</code> … <code>eN</code> lambda-rterms intended as arguments.</li>
</ul>
<p>The references correpond to an extension of the calculus of constructions by <em>definitional features</em>, and it gives a calculus named <em>λD</em>. The idea is to have a term that references either a definition, an axiom