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I'm working with xAct package. I've defined the tensor component values and my issue is that I want an expression involving Levi Civita symbols and tensor components, I don't know how to deal with it. The expression is something like $\epsilon_{abc}$T$_{ade}$ and other two index tensor components. Does anybody know how to deal with it? I try multipling the tensor T to the Levi Civita, but my output writes 'T' instead of the components of the tensor. Can anybody help me please? Thank you

user25578
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  • This is a duplicate of Contracting with Levi-Civita (totally antisymmetric) tensor. Most likely this functionality is poorly known even though it is one of the most important symbolic news in Mathematica 9. See also closely related Using the epsilon tensor in Mathematica – Artes Jul 06 '14 at 11:22
  • @Artes Well, he's asking about the xAct package, not the built-in tensor functionality. So it's not exactly a duplicate. – Teake Nutma Jul 06 '14 at 18:14
  • my principal sissue is that I've defined the tensor component values, and when I use ComponentValue command I obtain the correct output, but when I calculate, for example, a tensor product between my tensor and the levi civita symbol my output writes T.$\epsilon$ instead of make the product using the components. I've also tried using contract tensor, but the output is the same – user25578 Jul 06 '14 at 19:34
  • You'll have to post some code snippets, otherwise I can't quite figure out what you mean. But there's also the xAct Google Group where you can ask this question. – Teake Nutma Jul 06 '14 at 20:14
  • @TeakeNutma It's a duplicate, by the way the built-in functionality is by the same guy as xAct. – Artes Jul 06 '14 at 21:17
  • @Artes Well he isn't asking about a full contraction, so at best it's closely related. And given the fact it is a specific xAct question, I tend to disagree. But if OP is happy with the linked answer I'll shut up :). – Teake Nutma Jul 06 '14 at 21:48
  • @TeakeNutma With the question at hand it was the best one could give to link an appropriate post. So what is your problem? Could you explain or perhaps you should flag this as inappropiately closed or perhaps your comments are simply irrelevant? – Artes Jul 06 '14 at 22:17
  • My expression is $\textit{L}=\frac{C}{f}\sum\epsilon_{abc}(\bar{T}{ade}S^{\dg}\cdot(\vec{\nabla{\phi{db}}})B_{ec}+\bar{B}{ce}S\cdot(\vec{\nabla{\phi{bd}}})T_{ade})$. My tensor T is totally symmetric, and I've already defined the values of components, but when I try to multiply to Levi Civita mathematica doesn't seem to use that components, the output is only 'T'.$\epsilon$. Maybe I could do that operation using tables or list?? – user25578 Jul 07 '14 at 07:38
  • @Artes This question should not have been closed: the question is regarding a third-party package, while the answer in the linked question is about built-in functionality. – QuantumDot Sep 25 '16 at 20:31
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    @TeakeNutma This question is now open. Would you kindly post an answer when you get a chance? – QuantumDot Sep 26 '16 at 15:17

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