I am reading Itskov on tensor analysis, and he has this equation for second order tensors (5.17):
$\textbf{A} \otimes \textbf{B} \textbf{:} \textbf{X} = \textbf{A}\textbf{X}\textbf{B}$
However, I am reading a paper and the author uses (eqn 15):
$\left(\textbf{A} \otimes \textbf{B} \right)\textbf{:} \textbf{X} = \left( \textbf{B} \textbf{:} \textbf{X} \right)\textbf{A}$
Which is correct? Is this an order of operations issue? I don't believe it is because if we take the double dot product in Itskov's expression first, then we have a scalar with which to take the tensor product.