I am not sure how exactly to interpret this kind of notation.
I understand the second one to read sum of over $k$ of $\gamma_{k,j}$ is equal to zero. Is that the same as:
$\gamma_{1,1}+\gamma_{2,1}+\gamma_{3,1}\dots=0$
$\gamma_{1,2}+\gamma_{2,2}+\gamma_{3,2}\dots=0$
etc...
Thank you so much.
