deletions | additions       diff --git a/Combination.tex b/Combination.tex  index b47dd56..27bb1e0 100644  --- a/Combination.tex  +++ b/Combination.tex 
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\begin{vmatrix} \phi_{12} & \phi_{11} \\ \phi_{32} & \phi_{31}\end{vmatrix} &  \begin{vmatrix} \phi_{11} & \phi_{12} \\ \phi_{21} & \phi_{22}\end{vmatrix}   \end{bmatrix}  =  \begin{bmatrix}  \begin{vmatrix} \phi_{22} & \phi_{23} \\ \phi_{32} & \phi_{33}\end{vmatrix} &  \begin{vmatrix} \phi_{13} & \phi_{12} \\ \phi_{33} & \phi_{32}\end{vmatrix} &  \begin{vmatrix} \phi_{12} & \phi_{13} \\ \phi_{22} & \phi_{23}\end{vmatrix} \\  \begin{vmatrix} \phi_{23} & \phi_{21} \\ \phi_{33} & \phi_{31}\end{vmatrix} &  \begin{vmatrix} \phi_{11} & \phi_{13} \\ \phi_{31} & \phi_{33}\end{vmatrix} &  \begin{vmatrix} \phi_{13} & \phi_{11} \\ \phi_{23} & \phi_{21}\end{vmatrix} \\  \begin{vmatrix} \phi_{21} & \phi_{22} \\ \phi_{31} & \phi_{32}\end{vmatrix} &  \begin{vmatrix} \phi_{12} & \phi_{11} \\ \phi_{32} & \phi_{31}\end{vmatrix} &  \Psi{r_1,r_2}  \end{bmatrix}  \end{equation}