Recent content by nobraner

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    Covariant Derivation of the Ricci Tensor: Einstein's Method Now Online

    Bill, Finally found the time to fix this. One of my biggest weaknesses is ignoring the upper/lower covariant derivative convention. I guess I always think of covariant derivatives as always being covariant.
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    Covariant Derivation of the Ricci Tensor: Einstein's Method Now Online

    The full derivation of the covariant derivative of the Ricci Tensor as Einstein did it, is now available on line at https://sites.google.com/site/generalrelativity101/appendix-c-the-covariant-derivative-of-the-ricci-tensor For those who wish to study it.
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    Help Covariant Derivative of Ricci Tensor the hard way.

    Thanks for the advice, but anyone can do it that way. I'm trying to do it the way Einstein did it; the hard way. Einstein didn't know about the Bianchi Identities.
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    Help Covariant Derivative of Ricci Tensor the hard way.

    Then, how did Einstein get [SIZE="5"]\nabla_{μ}R_{αβ}=\frac{1}{2}g_{αβ}\nabla_{μ}R
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    Help Covariant Derivative of Ricci Tensor the hard way.

    [SIZE="5"]I am trying to calculate the covariant derivative of the Ricci Tensor the way Einstein did it, but I keep coming up with \nabla_{μ}R_{αβ}=\frac{∂}{∂x^{μ}}R_{αβ}-2\Gamma^{α}_{μ\gamma}R_{αβ} or...
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    Einstein Tensor; What is wrong here?

    I don't understand your declaration that \mu \nu are already taken. Does that mean we can never assume that such a metric as g^{\mu\nu} exists without first proving that it is so for the specific case of \nabla^{\mu}R_{\mu\nu}=\frac{1}{4}\nabla^{\mu}g_{\mu\nu}R
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    Einstein Tensor; What is wrong here?

    Start with \nabla^{\mu}R_{\mu\nu}=\nabla^{\mu}R_{\mu\nu} Insert \nabla^{\mu}R_{\mu\nu}=\nabla^{\mu}\frac{g_{\mu\nu}g^{\mu\nu}}{4}R_{\mu\nu} Contract the Ricci Tensor \nabla^{\mu}R_{\mu\nu} = \nabla^{\mu}\frac{g_{\mu\nu}}{4}R Thus...
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    Einstein Tensor; super simple derivation; where did I go wrong?

    If as you say, Professor Susskind is wrong, then I feel betrayed that a physicist of his stature would teach error.
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    Einstein Tensor; super simple derivation; where did I go wrong?

    Professor Lenard Susskind explicitly states in his YouTube videos that g^{\mu\nu}g_{\mu\nu}=\delta^{\mu}_{\nu} The product of the covariant and contravariant metric is the kroniker delta (the multiplicative identity matrix). Although, he does say somewhere that if you have \delta^{a}_{\nu}...
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    Einstein Tensor; super simple derivation; where did I go wrong?

    Start with \nabla_{μ}R^{\mu\nu}=\nabla_{μ}R^{\mu\nu} insert the multiplicative identity, expressed as the product of the covariant and contravariant metric \nabla_{μ}R^{\mu\nu}=\nabla_{μ}(g^{\mu \nu}g_{\mu\nu})R^{\mu\nu} contract the indices of the Ricci Tensor, to get...
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