help with Detg[]

[Ghazal G]

Hi everyone,

I am just starting to work with xPand. To start with, I am trying to get the GR quadratic action for scalar perturbations around flat FRW. However, I keep getting the warning that "the tensor Detg was not defined with DefProjectedTensor" 

The result after Integration by parts seems to be off and I think it has to do with the determinant factor. 

I am including the notebook here. Could someone help me figure out how I should do this. 

[Cyril Pitrou]

Dear Ghazal,

This is because you perform a conformal transformation before calling MyToxPand.

MyToxPand is a wrapper which does everything and among its steps it already performs a conformal transformation.

So the command you need to call is in fact simpler, see the notebook attached. I have basically removed you calls of

Conformal[g,gah2][...]

given that they are useless (and thus wrong, as it performs an extra conformal transformation).

Best,
Cyril Pitrou

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[Ghazal Geshnizjani]

Dear Cyril, 

thanks, that helps a lot. Is there a reason that background determinant is not evaluated automatically in the expression to be cancelled out with common factors in denominator? 

best,

Ghazal