Section EUTTG_principles.
Context {E : Type -> Type} {R1 R2 : Type} (RR : R1 -> R2 -> Prop).
Local Notation euttG := (@euttG E R1 R2 RR).
(* Make new hypotheses *)
(* Process itrees *)

Lemma euttG_ret: forall rH rL gL gH v1 v2,
RR v1 v2 -> euttG rH rL gL gH (Ret v1) (Ret v2).