Partial derivative with multiple indices

Question

Hello,

did anyone experience that a term like

\partial_{\mu}(\partial_{\nu}\phi^{m})

was not simplified to

\partial_{\mu\nu}\phi^{m} ?

I did trial and error, for example, by writing \partial{#}::PartialDerivative; , \partial{#}::PartialDerivative: , \partial{#}::PartialDerivative. or \partial{#}::Derivative; etc...but I did not solve the problem in any way. canonicalise seemed not to work. Thank you.

Answer 1

Might be because you mistyped the input; the following works just fine:

\partial{#}::PartialDerivative;
ex:= \partial_{\mu}{\partial_{\nu}{\phi^{m}};

produces $$\partial_{\mu\nu}{\phi^m}$$ immediately.