Definition bs_of_cfg := fst cfg.Definition share_of_cfg := fst (snd cfg).Definition fl_of_cfg := fst (snd (snd cfg)).Definition cnt_of_cfg := fst (snd (snd (snd cfg))).Definition negm_of_cfg := fst (snd (snd (snd (snd cfg)))).Definition orm_of_cfg := fst (snd (snd (snd (snd (snd cfg))))).Definition um_of_cfg := snd (snd (snd (snd (snd (snd cfg))))).

Lemma low_used : forall (cfg : BDDconfig) (ul : list ad) (x : BDDvar) (l r node : ad), used_node cfg ul node -> MapGet _ (fst cfg) node = Some (x, (l, r)) -> used_node cfg ul l.