|Definition:|| tensor of the second order with components where is the Kronecker delta, equal to 1 if i = j and 0 if i ≠ j|
Note 1 to entry: The components of the Kronecker tensor are independent of the base used. The inner product of the Kronecker tensor and a tensor or a vector is equal to this tensor or vector.
Note 2 to entry: When the properties of an anisotropic medium are represented at each point by a tensor quantity of the second order, this quantity reduces, in an isotropic medium, to the product of the Kronecker tensor and a scalar quantity. In practice, the quantity is then considered as a scalar quantity.