Definition BDDuniv_memo_put (cfg : BDDconfig) (x : BDDvar)
  (node node' : ad) :=
  match cfg with
  | (bs, (share, (fl, (cnt, (negm, (orm, um)))))) =>
      (bs, (share, (fl, (cnt, (negm, (orm, MapPut2 ad um node x node'))))))
  end.

Lemma not_zero_is_one : forall (cfg : BDDconfig) (node : ad), config_node_OK cfg node -> in_dom _ node (fst cfg) = false -> Neqb node BDDzero = false -> Neqb node BDDone = true.