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Timeline for Tensor Operators

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Sep 10, 2013 at 8:30 comment added joshphysics @zodiac Notice that $U$ is a representation of the group $G$ on a Hilbert space; it can potentially be a much different beast than $\rho$ which is a representation of $G$ on a finite-dimensional vector space. In particular, it need not be generated by the representation $\rho$ in the way you describe.
Sep 10, 2013 at 7:06 comment added xuanji In your question I did notice that $U$ and $\rho$ are constrained to both be representations of the same underlying group, but in the standard formulation, the transformation law of the vectors (the $\rho$) completely determines the transformation law of the tensors (the $U$), so I was wondering if there were some inconsistency. Unfortunately I'm not familiar enough with group representations to be sure.
Sep 10, 2013 at 7:01 comment added joshphysics You've simply described the standard formulation of tensors as multilinear maps that is used both in differential geometry and in algebra; I am well-aware of that stuff. Notice, in fact, that my candidate definition above is written precisely in terms of multilinear maps which is what you're describing here. The notion I want to define here, however, is a bit less straightforward than that I'm afraid.
Sep 10, 2013 at 6:52 history edited xuanji CC BY-SA 3.0
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Sep 8, 2013 at 20:35 comment added user4552 This generalizes straightforwardly from rotation to the Lorentz group, and can also be generalized to arbitrary diffeomorphisms.
Sep 8, 2013 at 6:57 history answered xuanji CC BY-SA 3.0