Iof proof for Lemma top wf:
(
x:!Void().!Void()) 
Type
by ((((((% Got to fix this %
Unfold `member` 0)
UCollapseTHEN (
UCRefine `isectEquality` [mk_var_arg `x']))
)
UCollapseTHEN (Fold `member` 0))
)
UCollapseTHEN (
UC(Auto_aux (first_nat 1:n) ((first_nat 1:n),(first_nat 3:n)) (first_tok :t) inil_term)))
UC.