Understanding Tensors & General Relativity

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I enjoyed this video about tensors very much. I would recommend it to anyone seeking to understand the concept in general and general relativity specifically.

https://vimeo.com/32413024

You can fast forward through the repetitive parts and try to place yourself in the role of beginner as you watch.

Do you think anything essential is missing in this presentation?
 
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I forgot to mention I found the emphasis on the association between basis vectors and components to be powerful. It leads to moving beyond thinking of a vector as an arrow to thinking of it as one of many possible associations between basis vectors and components. This generalized association is a good conceptual definition of a tensor in my opinion. It's a good way to find your footing as you explore.
 
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From $$0 = \delta(g^{\alpha\mu}g_{\mu\nu}) = g^{\alpha\mu} \delta g_{\mu\nu} + g_{\mu\nu} \delta g^{\alpha\mu}$$ we have $$g^{\alpha\mu} \delta g_{\mu\nu} = -g_{\mu\nu} \delta g^{\alpha\mu} \,\, . $$ Multiply both sides by ##g_{\alpha\beta}## to get $$\delta g_{\beta\nu} = -g_{\alpha\beta} g_{\mu\nu} \delta g^{\alpha\mu} \qquad(*)$$ (This is Dirac's eq. (26.9) in "GTR".) On the other hand, the variation ##\delta g^{\alpha\mu} = \bar{g}^{\alpha\mu} - g^{\alpha\mu}## should be a tensor...

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