\begin{tabbing}
(\=(MemberEqCD) \+
\\[0ex]C\=ollapseTHEN (IfLab `subterm` \+
\\[0ex]((MemberEqCD) 
\-\\[0ex]CollapseTHEN (
\-\\[0ex]IfLab `subterm` Id (Auto\_aux (first\_nat 1:n) ((first\_nat 1:n),(first\_nat 3:n)) (first\_tok 
\\[0ex]:t\=) inil\_term)))$\cdot$ \+
\\[0ex](Auto\_aux (first\_nat 1:n) ((first\_nat 1:n),(first\_nat 3:n
\-\\[0ex])) (first\_tok :t) inil\_term)))$\cdot$
\end{tabbing}