\begin{tabbing}
((\% Establish desired induction hyp \% 
\\[0ex]A\=ssert $\forall$$t$:$\mathbb{N}$. ($t$ $<$ $s$) $\Rightarrow$ $P$($t$)) \+
\\[0ex]CollapseTHEN (
\-\\[0ex]I\=f\=LabL \+\+
\\[0ex][`main`,OnHyps [7;5;4;3] Thin \% cleanup \% 
\\[0ex];`assertion`,((((RepD) 
\\[0ex]
\-\\[0ex]CollapseTHENM (InstHyp [$t$] 5))$\cdot$) 
\\[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}