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 used_nodes_preserved_used_node : forall (cfg cfg' : BDDconfig) (ul : list ad) (node : ad), BDDconfig_OK cfg -> used_nodes_preserved cfg cfg' ul -> used_node cfg ul node -> used_node cfg' ul node.