\begin{tabbing} (\=(((((((Unfold `guard` 0) \+ \\[0ex]CollapseTHENM (RepeatMFor 4 (D 0)))$\cdot$) \\[0ex]CollapseTHENM ( \-\\[0ex]B\=Lemma `squash\_functionality\_wrt\_implies`))$\cdot$) \+ \\[0ex]CollapseTHENM (HypBackchain))$\cdot$) \\[0ex] \\[0ex]CollapseTHENA ((Auto\_aux (first\_nat 1:n) ((first\_nat 1:n),(first\_nat 3:n)) (first\_tok :t \-\\[0ex]) inil\_term)))$\cdot$ \end{tabbing}