Every tensor has an associated spatial dimension and tensor order. Each tensor-quantity can be decomposed into scalar components for a given orthonormal basis of the proper dimension (except of . The physical-dimension of a scalar component of the tensor-quantity is equivalent to the physical-dimension of the tensor-quantity.
(<=> (And (Tensor-Quantity ?T) (= (Tensor-Order ?T) 0)) (Scalar-Quantity ?T))