on.ConstructorSeqTL" class="extype">ConstructorSeqTL</a>.</p><h4>Recursion and Induction functions</h4><p>These are defined recursively, first for each introduction rule and then for the inductive type as a whole. A subtlety is that the
scala type of the <code>rec_W,X</code> and <code>induc_W, Xs</code> functions depends on the scala type of the codomain <code>X</code> (or family <code>Xs</code>).
To make these types visible, some type level calculations using  implicits are done, giving traits <a href="ind