deletions | additions       diff --git a/4-Dimensions.tex b/4-Dimensions.tex  index b5fe9c4..c09bc6c 100644  --- a/4-Dimensions.tex  +++ b/4-Dimensions.tex 
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-\textbf{l}({_z\textbf{r}_1} \times {_z\textbf{r}_2} )  \end{equation}  Therefore making a 4x4 skew symmetric  matrix \begin{equation} \textbf{r}_1 \otimes \textbf{r}_2 =  \begin{bmatrix}