Thank you, regardless of my example this seems quite relevant for windows users. I will report if I

I need to do some calculations with a perturbed 7d FLRW metric, in particular I need the perturbed

Hi, In the document that you have attached I don't see any variation of the the Ricci scalar, so

Dear Mattia, Thank you for the warm welcome. Please accept my apologies for the delayed response.

Hello everyone, I am happy to announce a new xAct package: https://arxiv.org/abs/2609.07826. It is

Hello everyone. I am working with Plebanski - Carter separablity ansatz to obtain Kerr metric. I have

The problem is that delta has the structure of index-down,index-up: In[24]:= SlotsOfTensor@delta Out[

Thank you for the response. I think the problem was that it does not seem to be true that "Once

Hi Dear! Welcome to the xAct community! Please Quit[] , and Run again properly as :<< xAct`xCPS

Hi everyone, I would implement a tensor A_{\mu}=( A_0(t), \vec{A(t)}) using C Tensor; how can do it?

Hello everyone. I am a Relativist doing his first steps in the xAct world. So, any advice regarding

You're very welcome! On Mon, 13 Jul 2026 at 16:40, Jairo Villalobos <grelati...@gmail.com

Hi! I am no expert on xCoba but if you use PDsph[{1, -sph}][Faraday[{0, -sph}, {0, -sph}]] //

I agree with you, Joffrey. That option should be included in the private functions CovDTensor1,

Hi, 1. DefCoordinates is not recognized command, you have to use DefChart: DefChart[nameofchart, M4,

I installed a new binary -- that worked - Thanks On Sunday, April 19, 2026 at 7:54:24 PM UTC-4 James

Hi Héloïse, These calculations can quickly become very messy so it's good to simplify the

Hi, can you post the actual errors you get and describe what you did to compile it ? Best, Alfonso.

This is an issue related to the increased anti-malware protections that Apple has added to MacOS over

Dear Jose, sorry for bringing back this very old thread. I faced the same problem as Geoffrey and

Hello Nat, Welcome to the great land of Mathematica! I've actually just released an xAct package

Hello xAct community, I want to share a new package: xAlpha. This uses xPand to compute nonlinear

That worked thanks! On Thursday, April 30, 2026 at 5:21:14 PM UTC-4 Juan Margalef wrote: You have to

Hi all, I am having an issue when multiplying a CTensor object with a scalar that has defined label

Several comments: 1. Instead of CommutativityOfProduct -> None use CommutativityOfProduct ->

UseDimensionStart[] forces certain expressions to be zero when applying ToCanonical. It checks if

Dear Juan, I will have to take a closer look then. A huge thanks for your help! Cheers, Nils Le

Hi Alejandro, I suspect there is some inconsistency somewhere about the use of upper/lower components

Hi everyone, I am very new to xAct and was trying to reproduce the results in Eqs. C.23 to C.25 of

Hi AC, We would need a bit more information to help you. Provide a minimal working example of the