\begin{tabbing}
(\=(Assert ($a$+$n$+({-}$n$)) $<$ ($b$+$n$+({-}$n$))) \+
\\[0ex]CollapseTHENM ((Auto\_aux (first\_nat 1:n) ((first\_nat 
\-\\[0ex]2:n),(first\_nat 3:n)) (first\_tok :t) inil\_term)))$\cdot$
\end{tabbing}