∀ {Γ : Type u_1} {R : Type u_2} [inst : PartialOrder Γ] [inst_1 : AddMonoid R] (x : HahnSeries Γ Rᵃᵒᵖ),
  (fun x => { coeff := fun a => AddOpposite.op ((AddOpposite.unop x).coeff a), isPWO_support' := ⋯ })
      ((fun x => AddOpposite.op { coeff := fun a => AddOpposite.unop (x.coeff a), isPWO_support' := ⋯ }) x) =
    x