\begin{tabbing}
(\=(((((RenameVar `g' 3) \+
\\[0ex]CollapseTHENM (Unfold `decidable` 3))$\cdot$) 
\\[0ex]CollapseTHENM (((With 
\-\\[0ex]$\lambda$\=$x$,$y$. case $g$($x$,$y$) of inl($a$) =$>$ tt $\mid$ inr($b$) =$>$ ff (D 0)) \+
\\[0ex]CollapseTHENA (
\-\\[0ex](Auto\_aux (first\_nat 1:n) ((first\_nat 1:n),(first\_nat 3:n)) (first\_tok :t) inil\_term)))$\cdot$))
\\[0ex]$\cdot$\=) \+
\\[0ex]CollapseTHENM (Reduce 0))$\cdot$
\-
\end{tabbing}