deletions | additions       diff --git a/Summary.tex b/Summary.tex  index dba7d6b..d8ca59c 100644  --- a/Summary.tex  +++ b/Summary.tex 
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\partial_x\partial_z & \partial_y\partial_z & -\partial_y^2-\partial_x^2   \end{bmatrix} \\ \\  \nabla^2_{scalar} = \nabla\cdot\nabla =\partial_x^2 + \partial_y^2 + \partial_z^2 = \frac{1}{3}Tr(\nabla^2)  \\\\ \nabla^4 \\\\