Section BDDvar_make_results.
Variable cfg : BDDconfig.
Variable ul : list ad.
Variable x : BDDvar.
Hypothesis cfg_OK : BDDconfig_OK cfg.
Hypothesis ul_OK : used_list_OK cfg ul.
Definition BDDvar_make := BDDmake gc cfg x BDDzero BDDone ul.

Lemma BDDvar_make_used_nodes_preserved :
used_nodes_preserved cfg (fst BDDvar_make) ul.