Tensor help -- Write out this tensor in a simplified sum

user1139
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Homework Statement
Write out $$F_{\alpha\beta}F^{\alpha\gamma}$$ in a simplified sum where $$F$$ is the stress tensor and Einstein summation convention is implied.
Relevant Equations
$$F_{\mu\nu}$$ is the usual stress tensor
I managed to write

$$F_{\alpha\beta}F^{\alpha\gamma}=F_{0\beta}F^{0\gamma}+F_{i\beta}F^{i\gamma}$$

where $$i=1,2,3$$ and $$\gamma=0,1,2,3=\beta$$.

How do I proceed?
 
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It's like two "for" loops in programming:

0) You have four terms when summing ##\alpha##

1) Start with ##\gamma## and expand to four equations for 0,1,2, and 3 with ##\beta## still there.

Repeating with the same expansion with ##\beta##, you should now have 16 equations for ##F _{\beta}^{\gamma}##.
 
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