∀ {𝕜 : Type u_1} {E : Type u_2} [inst : RCLike 𝕜] [inst_1 : NormedAddCommGroup E] [inst_2 : InnerProductSpace 𝕜 E]
  (x : TensorProduct 𝕜 𝕜 E), (TensorProduct.lidIsometry 𝕜 E) x = (TensorProduct.lid 𝕜 E) x