\begin{tabbing}
(\=(((RepD) \+
\\[0ex]CollapseTHENM (RecCaseSplit `nth\_tl`))$\cdot$) 
\\[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}