simp[Tensor2D.transpose]
size0 size1 : ℕ
data : TensorIndex2D size0 size1 → ℤ
⊢ Tensor2D.transpose (Tensor2D.transpose { size0 := size0, size1 := size1, data := data }) =
    { size0 := size0, size1 := size1, data := data }
size0 size1 : ℕ
data : TensorIndex2D size0 size1 → ℤ
⊢ (fun ix => data (TensorIndex2D.transpose (TensorIndex2D.transpose ix))) = data