Definition unstratify (n:nat) (p:sinv n) : knot * other -> T := fun w =>
    match w with (existT _ nw w',o) =>
      match decompose_nat nw n with
        | inleft (existT _ m Hm) => snd (proj1_sig (floor m (S nw) (eq_rect  n _ p (m + S nw) Hm))) (w',o)
        | inright H => T_bot
      end
    end.

Lemma stratify_unstratify : forall n p H, proj1_sig (stratify (unstratify n p) H n) = p.