xAct Tensor Computer Algebra

Hello everyone, I have complicated Lagrangian with terms like EinsteinCD[a,b]CD[-c][CD[-b][F[]]]CD[c]

Related with xTensor: I attach a part of my work. I've tried to write the superpotential (Written

Dear Leo, Jose, et al., I think Leo explained the process best. In terms of how hackathons go, say

Hi, The fact that this involves the combination of xTras and Mathematica 11 makes me think that it

Hi, This is a good point. I had never thought of this case, and I'm afraid VarD does not handle

It's difficult to rule out the presence of bugs in software of the complexity of xAct, but before

Hi, I reattach your notebook with the computation I think you want. I must say that I generally don

Dear Thomas, Thanks a lot for your reply. Now I understand the structure, and it works very well.

Hi Soham, I never thought of doing something like that. We can organize some sort of xAct-related

Hi, The PacletInfo files have been removed from the xAct tarballs, to avoid problems while loading

Thank you very much for your answer Jose! I will definitely come back here with more questions at

Hi all, We have released xAct version 1.2.0. The main motivation is the addition of the new xAct

Hi! In Mathematica (and xAct) you can define anything recursively like f[0] = something f[n_] := some

Dear Leo, Thanks, hope you are well too! Thank you very much for the example notebook, it is indeed

Try taking a look at https://groups.google.com/g/xAct/c/YW4rPKK7I98 On Saturday, October 2, 2021 at 3

Dear all, Would anyone be able to share their experiences working with the relativistic kinetic

Hi, I attach a notebook with some basic commands using VarD (from xTensor) and VarL (from xTras) to

Hi, I guess the other question you found is https://groups.google.com/g/xact/c/u6-RQP-T0JI/m/

Hi Albin, This notebook was very useful to understand what is going on. I attach it again showing how

Hi, This notebook contains the line SetOptions[ToCanonical, UseMetricOnVBundle -> None] which

Hi, Your code has various name conflicts: d is both a constant symbol and an index, g is both a

Hi all, I'm trying to use xPPN to calculate the PPN parameters for a vector-tensor theory. I have

Hi, thanks for the comments, I have fixed the things you found. I am trying yet another way to get

Yes, you can extend this computation to include other curvature tensors. You just need to add more

Thank you, Jose! That worked perfectly, using the full paths for the mprep and mcc commands. Footnote

Hi, My guess is that some xAct definition(s) (either built-in or from your own code) is interfering

Hi, Your expression pertB contains epsilonmet[i, j, k] covD[-j][epsilonmet[k, l, m] xi[-l] B[-m] ]

Dear Omar, I received your message, but it didn't contain any question. The reason for the (maybe

Let me also add to Jose's answer. If you want the divergence of B to automatically vanish, you

Hi, I don't think we have xAct functionality that can do this sort of thing automatically. In