\begin{tabbing}
(\=(((Unfolds ``l\_member last`` 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 (Assert $\parallel$$L$$\parallel$ $>$ 0  
\\[0ex]
\\[0ex]
\\[0ex]THENL [((((RW assert\_pushdownC ({-}1)) 
\\[0ex]CollapseTHENA ((Auto\_aux (first\_nat 1:n
\-\\[0ex])\= ((first\_nat 1:n),(first\_nat 3:n)) (first\_tok :t) inil\_term)))$\cdot$) \+
\\[0ex]Colla\=pseTHEN (Easy))$\cdot$;\+
\\[0ex]
\\[0ex]
\\[0ex]((InstConcl [$\parallel$$L$$\parallel$ {-} 1]) 
\-\\[0ex]CollapseTHEN ((Auto\_aux (first\_nat 1:n) ((first\_nat 
\-\\[0ex]2:n),(first\_nat 3:n)) (first\_tok :t) inil\_term)))$\cdot$]))$\cdot$
\end{tabbing}