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I came across the following expression:

$$\frac{\partial^{i_1+\cdots+i_m}P(x_1,\ldots,x_m)}{\partial x_1^{i_1}\cdot\cdot\cdot \partial x_m^{i_m}}$$

for $P(x_1,\ldots,x_m)$ a polynomial in $m$ variables $x_1,\ldots,x_m$, and I must say that I find it rather confusing, as I've never encountered this notation before.

So my question is: Given a monomial of the form $x_1^{j_1}\cdots x_m^{j_m}$, what does $\dfrac{\partial^{i_1+\,\cdots\,+i_m} x_1^{j_1} \cdots x_m^{j_m} }{\partial x_1^{i_1}\cdots \partial x_m^{i_m}}$ look like?

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    I'm curious: Where did you come across that expression?2012-04-21
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    @sssss : Can you tell me where you learned to use $\TeX$ for posting in this forum. Lot's of people who post here do the same thing you did: they write things like {{a}^{2}} instead of a^2, and you did lots of things like that here. I changed it since I don't want to encourage newbies to think things like that are needed.2012-04-21

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