∀ {𝕜 : Type u_2} {H : Type u_1} [inst : RCLike 𝕜] [inst_1 : SeminormedAddCommGroup H] [inst_2 : InnerProductSpace 𝕜 H]
  (x : Hᵐᵒᵖ), ‖MulOpposite.unop x‖ ^ 2 = RCLike.re (inner 𝕜 (MulOpposite.unop x) (MulOpposite.unop x))