Short notation for indix (anti) commutation
Nils Marion
Dear xAct community,
I wanted to know if it is possible to automatically replace an expression involving (anti-)commutation of indices, such as
Ta Rb ± Tb Ra
by a compact (anti)symmetrized form like
T_[a R_b]
in the output of xAct.
Is there a built-in function or a recommended way to achieve this?
Best regards,
Nils
Thomas Bäckdahl
Hi!
Yes. You can use the SymMaipulator package for this.
See for instance
https://groups.google.com/g/xact/c/O6oTsKzfd8c/m/oZjINA3oAgAJ
for an example on how this can be done.
It is important to not have several terms in the left hand side of
your replacement rules. Therefore one needs to replace one term by
the sum of its symmetric and antisymmetric parts.
Regards
Thomas
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Nils Marion
Dear Thomas,
Thank you very much for your quick reply. I had completely missed the SymManipulator package, which looks like it perfectly fits my needs.
Have a great day,
Nils