Talk:Multi-index notation

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[edit] Derivative Notation

The article uses the :D notation for derivatives. In most microlocal analysis literature :\part is used instead, and :D means something else. Specifically;

\part^{\alpha} := \part_{1}^{\alpha_{1}} \part_{2}^{\alpha_{2}} \ldots \part_{n}^{\alpha_{n}} where \part_{x_i}^{m}:=\part^{m} / \part x_{i}^{m}

And :D is defined by;

D_{x_i}^{m}:=(-i)^m \part^m / \part x_i^m

So

D^{\alpha} := D_{1}^{\alpha_{1}} D_{2}^{\alpha_{2}} \ldots D_{n}^{\alpha_{n}}:= (-i)^{|\alpha|} \part^\alpha

However, I'm not sure if this is how it is in other branches of mathematics. Multi-index notation made simple formulas very complex, and very complex formulas no understandable, like tensors on lections. We see many times as mathematicians start confusion, if they use it. So, don’t use it if you can.