\begin{tabbing}
(\=(((Unfold `guard` 0) \+
\\[0ex]CollapseTHEN (RepD))$\cdot$) 
\\[0ex]CollapseTHENA ((Auto\_aux (first\_nat 1:n
\-\\[0ex]) ((first\_nat 2:n),(first\_nat 3:n)) (first\_tok :t) inil\_term)))$\cdot$
\end{tabbing}