Is This Invariant Calculation Correct?

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SUMMARY

The discussion centers on the calculation of the invariant \( E^{\alpha \beta} E_{\alpha \beta} \) using the metric tensor \( g_{\alpha n} g_{\beta m} E_{n m} E^{n m} \). It is concluded that the equation presented is incorrect due to the improper handling of indices, specifically the use of dummy and free indices. The participants emphasize the necessity of clarity in notation to avoid confusion in tensor calculations.

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Homework Statement



Calculate the invariant
[tex] E^{\alpha \beta} E_{\alpha \beta}[/tex]



Homework Equations





The Attempt at a Solution


we apply the metric in this case,
[tex] E^{\alpha \beta} E_{\alpha \beta} = g_{\alpha n} g_{\beta m} E_{n m} E^{n m}[/tex]

is that even correct?
 
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Nusc said:
we apply the metric in this case,
[tex] E^{\alpha \beta} E_{\alpha \beta} = g_{\alpha n} g_{\beta m} E_{n m} E^{n m}[/tex]

is that even correct?

No, that equation is non-sensical...on the lefthandside [itex]\alpha[/itex] and [itex]\beta[/itex] are dummy indices (they are being summed over)...on the righthandside they are free indices and you also have [itex]m[/itex] and [itex]n[/itex] appearing 3 times (which is notational nonsense).


I assume you are given either [itex]E^{\alpha \beta}[/itex] or [itex]E_{\alpha \beta}[/itex]?
 

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