“…Furthermore, for any tensor fields τ = ( τ ij ) i , j = 1, n and ζ = ( ζ ij ) i , j = 1, n , we let div τ be the divergence operator div acting along the rows of τ , and define the transpose, the trace, the tensor inner product, and the deviatoric tensor, respectively, as where is the identity matrix in ℝ n × n . Additionally, we define the following tensorial and vectorial functional spaces (see , Section 2.2 for details): and …”