(* Need the mutual induction scheme for the next lemma! *)
Scheme nom_val_ind' := Induction for nom_val Sort Prop
 with  nom_env_ind' := Induction for nom_env Sort Prop.Combined Scheme nom_mutual from nom_val_ind', nom_env_ind'.

Lemma nom_envsubst_lc : (forall rho, forall e, lc_exp e -> lc_exp (nom_envsubst rho e)).