xAct Tensor Computer Algebra

Hi again! I tried another thing. You can modify the order the tensors are sorted before

my question is why after that i have defined my metric, i will get the contravariant and covariant

Hi Alfonso, Thank you for your swift reply! Thank you for your comment on dx and using dX. I managed

Hi, ToCanonical is the function to check whether an expression is 0. There are two comments to make

Yes, we have the function SeparateMetric for that. It will make explicit all metric contractions. Try

Hi, The CTensor and TensorValues approaches are alternative and complementary. Each one has

Hi everyone, I would like to anounce the release of a new package called xBrauer. This package allows

Hi, There are a few issues here: 1) With symbolic components, SetCMetric cannot compute the sign of

Hi! This is not how patterns work in Mathematica. Read the help in Mathematica. For instance "

Hi, If I understand correctly you have a background metric that can be decomposed as 1+4 by diagonal

Hi, You can compute the epsilon tensor of met with epsilon[met]. Then you can compute contractions

Hi, First you can use the option BackgroundFieldMethod = True to turn off all second order

Hi, Can you provide a complete set of inputs (or even better a small notebook) where we can see an

Hi, Do you get the path to xTensor.m when you evaluate this line? FileNames[FileNameJoin[{$

Hi, I don't think I understand this question. The perturbation of RiemannCD[-a, -b, -c, d] is

Hi There, I am trying to derive equation 7 and 8 using equations 1-6 in the attached file. I am

Dear all, I am using xPand to compute the tensor perturbations in a theory with higher derivatives.

Hi! This depends a bit on how complicated expression you should be able to handle, but to handle some

Hi, There are several ways to do this. A possibility is to use xTensor's internal tool to define

Hi! In general it is not a great idea to make rules that tries to replace several terms with

thank you for your alternative proposal! Thomas Bäckdahl schrieb am Donnerstag, 9. März 2023 um 17:13

Hi! This seems a bit annoying. Unfortunately Solve can do some random choices. To be sure that you

oh..this is great..thanks everyone.. this helps a lot On Wednesday, March 1, 2023 at 6:56:18 AM UTC+5

Hi Jose, Thank you for your feedback. Sorry for the late reply. I was traveling. Fortunately, I

Hello, How can we perform the holographic renormalisation of U(1) gauge field in the asymptotically

Hi, This behavior is expected in all of xAct. Every symbol used must be defined with a unique type,

Hi Nitol, I'm not sure how you wanted to use VarD to integrate by parts and discard total

Hi, Yes, you can define tensor fields with indices in different vector spaces, like two tangent

Hi, There were three issues: 1) You were using a phi function without first declaring it with

Hi, Answers inlined. On Wednesday, February 8, 2023 at 6:56:06 AM UTC-6 salvam...@hotmail.com wrote: