I'm using a mixture of
Part to try and extract the arguments of a function that I need.
I'm using a function such as $J^\mu(1,2,3)$
and I'll be trying to represent this as
J[mu,Range[1,3]]or more generally for any index or any number of arguments,
I'll need to select the first element, i.e the index of this function every time, and then I'll need to select a few consecutive elements of the list. I.e; I'll need to select terms such as
I've tried using some variations of
Span inside the
Partargument, but I'm struggling to solely take the first variable, plus some extras.
Particularly, I'm trying to program the Berends-Giele recursion relation for n-gluons.
Any help would be much appreciated.
To show an example:
gives a result of
as expected. When I take
which is not expected.
What I'd like is something like
Is that possible using