<<xAct`xTensor`

<<xAct`xTras`

<<xAct`xCoba`

Manifold

$DefInfoQ=False;
$Post=ScreenDollarIndices;

DefConstantSymbol[Dim,PrintAs->"D"] (* dimension D*)
DefConstantSymbol[s,PrintAs->"s"] 
DefConstantSymbol[γ,PrintAs->"γ"] 
DefConstantSymbol[α,PrintAs->"α"] 
DefConstantSymbol[β,PrintAs->"β"] 
DefConstantSymbol[ξ,PrintAs->"ξ"] (* weight *)

DefManifold[M,Dim,{a,b,c,d,i,j,k}]
DefMetric[-1,g[-a,-b],CD,{";","∇"},PrintAs->"g"];

$DefInfoQ=False;

$CommuteCovDsOnScalars=True;(* commutation of CovDs on scalars*)

DefTensor[ϕ[],M]

expr=Sqrt[Detg[]]EinsteinCD[-a,-b] RicciScalarCD[] CD[a][ϕ[]] CD[b][ϕ[]]