\begin{tabbing}
(\=(((((Unfolds ``l\_before`` 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 (D 0))$\cdot$) 
\\[0ex]CollapseTHENA (
\-\\[0ex](Auto\_aux (first\_nat 1:n) ((first\_nat 1:n),(first\_nat 3:n)) (first\_tok :t) inil\_term)))$\cdot$
\end{tabbing}