of recursive definitions and diagonals (i.e., fixed points).</p><div class="fullcomment"><div class="comment cmt"><p>Much of  the richness of HoTT is in the definitions of <code><code>Inductive types</code></code> (and their indexed  counterparts)
and of (dependent) functions on these by recursion and induction
These are implemented using several layers of recursive definitions and diagonals (i.e., fixed points). In HoTT,
recursion and induction are applications of (dependent) functions <code>rec_W,X</code>