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 node_preserved_bs_reachable_1 :
forall bs bs' : BDDstate,
BDDstate_OK bs ->
forall (n : nat) (node node' : ad),
n = nat_of_N (bs_node_height bs node) ->
node_preserved_bs bs bs' node ->
nodes_reachable bs node node' -> nodes_reachable bs' node node'.