Section Components.
Variable cfg : BDDconfig.
Hypothesis cfg_OK : BDDconfig_OK cfg.
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 reachable_node_OK_1 :
forall (bs : BDDstate) (n : nat) (node1 node2 : ad),
BDDstate_OK bs ->
n = nat_of_N (bs_node_height bs node1) ->
node_OK bs node1 -> nodes_reachable bs node1 node2 -> node_OK bs node2.