In GR the metric can raise or lower indices, but which index will it raise in this case:(adsbygoogle = window.adsbygoogle || []).push({});

[itex] \delta^{ij} \partial_i \xi_j [/itex]

is it,

[itex] \partial^j \xi_j [/itex]

or,

[itex] \partial_i \xi^i [/itex]

Or are these equal?

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# Homework Help: Rasing and lowering indicies

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