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+2 votes

Hi,

When I apply the command combine() on

$ ( \Gamma ^ { a } ) _ { \beta } { } ^ { \gamma } ( \Gamma _ { c d } ) _ { \gamma }{ }^{ \alpha } $,

I get

$ ( \Gamma _ {c d} \Gamma ^ {a} ) ^ { \alpha } { } _ { \beta }$

while expecting

$ ( \Gamma ^ {a} \Gamma _ { c d } ) _ { \beta }{ } ^ { \alpha }$.

Am i doing something wrong?
(In case not rendering tex, i added image tex)

In addition, Is there any way to tell such structures to Cadabra;

$ A _ {a} B ^ {a} = - A ^ {a} B _ {a} $.

Since our metric is antisymmetric, the shape of the contraction matters.

Thanks in advance :)

asked in General questions by
edited

1 Answer

0 votes

Thanks for the bug report! The combine() issue has recently been fixed in git. As for the northeast / southwest convention, I would just declare the index positions to be fixed and include explicit metrics. But perhaps Kasper has a better answer.

answered ago by (180 points)
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