- #1
Niles
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Homework Statement
I have the following rank-2 tensor
[tex]
T = \nabla \cdot \sum_{i}{c_ic_ic_i}
[/tex]
I would like to write this using index notation. According to my book it becomes
[tex]
T_{ab} = \partial_y \sum_{i}{c_{ia}c_{ib}c_{iy}}
[/tex]
Question: The change [itex]\nabla \rightarrow \partial_y[/itex] and [itex]c_i \rightarrow c_{ia}[/itex] I agree with. However, it is not clear to me why my book uses the same index [itex]y[/itex] for [itex]\partial_y[/itex] as it does for [itex]c_{iy}[/itex]. Why are we allowed to do that?
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