Module red_one := ext_red_one invert.
Export red_one.
Set Bullet Behavior "Strict Subproofs".
Set Implicit Arguments.
(* Lemma Par_fv_preservation: forall G D x a b, Par G D a b -> x `notin` fv_tm_tm_tm a -> x `notin` fv_tm_tm_tm b. *)

Lemma reduction_in_Par : forall a a', reduction_in_one a a' -> forall G D, Par G D a a'.