epsilon tensors and Gdelta

[konstantinos.pallikaris]

Dear all,

Has the Gdelta bug, reported for example in

groups.google.com/g/xact/c/8t5gQIXtKrc

groups.google.com/g/xact/c/bUE6OpKyEHk

groups.google.com/g/xact/c/6YoufE0zqpg/m/s9hgz1A-AwAJ

been fixed in the 1.1.5 version? I still see ``troubling'' commentary in the relevant section of xTensor.nb, and I am unsure if any change has been implemented in the m file. Can you confirm please?

Also, when I deactivate the automatic Gdelta expansion with

Gdelta /: (f_ /; f === Times)[expr1___, gdelta_Gdelta, expr2___] =.

I still have the following issue: whenever two epsilons are in the expression, the program outputs an expanded Gdelta, without me calling the Expand command. This is not the case of course when I write the Gdelta explicitly (this works fine). Is there a way to  fix this with some command?

Thanks,

Kostas

[Jose]

Hi,

This was "fixed" in the sense of going directly to expansion into products of normal deltas, rather than keeping the result in terms of compact Gdelta terms. The algorithm that computes the latter is still to be fixed, but is currently not being used.

Cheers,

Jose.