[cadabra-discuss] Question: on produle with implicitindex
derivatives  Kasper Peeters kasper.peeters at aei.mpg.de Thu Apr
1 10:05:38 BST 2010  Hi Mathieu,  Well, it's somewhat of a
feature, in the sense that I can explain the logic. Let's start
from   and look at the expression    D(D(F) H);  In order to
apply the product rule, you have to know how the outer 'D'
commutes with the 'D(F)', in order to determine the sign for the
D(F) D(H)  term. Since D(F) has an implicit index, and D(...)
has too, there is no way to know what this sign is. Hence
cadabra refuses to apply the product rule.  Can you explain why
you expected this to give a result, and what you would like the
result to be? (I suspect that it is related to making 'D'
anticommuting, right?).   More information about the cadabra-
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