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 cons_OK_list_OK :
forall (cfg : BDDconfig) (ul : list ad) (node : ad),
used_list_OK cfg (node :: ul) -> used_list_OK cfg ul.