\begin{tabbing}
(\=(((Unfold `guard` 0) \+
\\[0ex]CollapseTHEN ((Auto\_aux (first\_nat 1:n) ((first\_nat 1:n
\-\\[0ex])\=,(first\_nat 3:n)) (first\_tok :t) inil\_term)))$\cdot$) \+
\\[0ex]CollapseTHEN (HypBackchain))$\cdot$
\-
\end{tabbing}