deletions | additions       diff --git a/4-Dimensions.tex b/4-Dimensions.tex  index 7a8ad65..fff9b37 100644  --- a/4-Dimensions.tex  +++ b/4-Dimensions.tex 
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-\textbf{j}({_x\textbf{r}_1} \times {_x\textbf{r}_2} )  +\textbf{k}({_y\textbf{r}_1} \times {_y\textbf{r}_2} )  -\textbf{l}({_z\textbf{r}_1} \times {_z\textbf{r}_2} )  \end{equation}  Therefore making a 4x4 matrix \begin{equation}  \textbf{r}_1 \otimes \textbf{r}_2 =  \begin{bmatrix}  \end{bmatrix}  \end{equation}