\begin{tabbing}
(\=(Unfolds ``not strict\_part`` 0) \+
\\[0ex]CollapseTHEN (((RepD) 
\\[0ex]CollapseTHENA (
\-\\[0ex](Auto\_aux (first\_nat 1:n) ((first\_nat 1:n),(first\_nat 3:n)) (first\_tok :t) inil\_term)))$\cdot$))
\\[0ex]$\cdot$
\end{tabbing}