Contracting Tensors: Multiply by g^αρgασ?

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Discussion Overview

The discussion revolves around the contraction of tensors, specifically the Ricci tensor, and the appropriate use of the metric tensor in this context. Participants express confusion regarding the ordering of indices and the general process of tensor contraction.

Discussion Character

  • Exploratory, Debate/contested, Conceptual clarification

Main Points Raised

  • One participant questions whether to multiply by g^{\alpha\rho}g_{\alpha\sigma} when contracting R^{\sigma}_{ \mbox{ }\mu\nu\rho} to R_{\mu\nu}, indicating confusion about index ordering.
  • Another participant points out that previous threads exist on the topic, suggesting that the discussion may be repetitive.
  • A participant expresses dissatisfaction with earlier answers and emphasizes a lack of understanding regarding the order of indices in tensor contraction.
  • One participant suggests that concerns about the answers should be addressed within the same thread rather than starting a new one.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the correct approach to tensor contraction or the importance of index ordering, indicating that multiple views and uncertainties remain in the discussion.

Contextual Notes

Participants express confusion about the ordering of indices and the implications of this ordering on tensor contraction, but do not clarify specific assumptions or definitions that may be influencing their understanding.

pleasehelpmeno
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When contracting R^{\sigma}_{ \mbox{ }\mu\nu\rho} to R_{\mu\nu}

Should one multiply by g^{\alpha\rho}g_{\alpha\sigma}? I often get confused with ordering of indices and such like
 
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there was no real answer, ignore the ricci tensor i just mean in general then, I don't really understand the order in which the indices should go, if it even matters at all.
 
If you're not satisfied with the answers, you should say that in the same thread, not start a new one.
 

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