6.25.3 Can you answer these questions?

6.25.3.1 Equation of Motion: Perturb Scalar Field and flat FLRW Metric (xAct)

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=233105

Is there a way to get the equations of motion (eom) of a scalar field from a Lagrangian in a perturbed FLRW metric? I want to perturb the field as well as the metric to 1st order. What I did so far: 
 
... 
[physics] [xact]
 

asked by kalle https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=68748 1 vote

6.25.3.2 Is there any way to change the box-formatting behavior thoroughly?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=233100

Background 
The box-formmating behavior is affected by the downvalues of the symbol  MakeBoxes . But the formatting behavior is not exactly ... 
[front-end] [evaluation] [cells] [implementation-details] [boxes]
                                                                                  

                                                                                  
 

asked by asd1dsa https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72876 2 votes

6.25.3.3 How to get colors at points in Graphics3D?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=233287

To get the color at a 2D point in  Graphics  you can  Rasterize  it and look up the pixel value, but not for ... 
[graphics3d] [color] [image3d] [textures] [imagevalue]
 

asked by M.R. https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=403 2 votes