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Is there any simple way to have multiple indices on a single derivative? If I define a derivative in the usual way

\delta{#}::Derivative;

then \delta{\mu\nu} is interpreted as a second derivative. I would like \delta{\mu\nu} to represent a single derivative (thus satisfying the product rule) but with multiple indices. This is important for the implementation of derivatives with respect to tensors for example.

in General questions by (130 points)

Are you really looking for derivatives like that, or is the actual aim to be able to write something like δS/δAμν?

Well, I actually need something like δBμν/δAρσ. At the moment I have to use 'vary' to compute δBμν and then set δAρσ1 at the end to extract δBμν/δAρσ. But then if I have a more complicated expression such as δBμν/δAρσ+BμνBρσ, I cannot simply substitute whatever expression I have for Bμν into it as the derivatives aren't automatically calculated. So I calculate the derivative separately and substitute in the expression. The problem with that is that I still have to define $\delta{\mu\nu} (= \delta/\delta A^{\mu\nu})asaderivativesothatCadabragetstheindicesrightinthesubstitutions.Since\delta\{\mu\nu}$ is a second derivative, my calculation would clash if I perform an operation such as product_rule, thus I don't use δμν for anything other than a dummy variable that gets replaced by the derivative I obtained with vary. I was just wondering if there is any easier/cleaner route to this and it seems that a derivative with multiple indices would solve my problem.

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