FourVector[p, mu] is the 4-dimensional vector p with
Lorentz index mu.
A vector with space-time Dimension D
is obtained by supplying the option Dimension -> D.
The shortcut FourVector is deprecated, please use
FV instead!
FourVector[p, \[Mu]]\overline{p}^{\mu }
FourVector[p - q, \[Mu]]\left(\overline{p}-\overline{q}\right)^{\mu }
StandardForm[FourVector[p, \[Mu]]]
(*Pair[LorentzIndex[\[Mu]], Momentum[p]]*)StandardForm[FourVector[p, \[Mu], Dimension -> D]]
(*Pair[LorentzIndex[\[Mu], D], Momentum[p, D]]*)FourVector is scheduled for removal in the future
versions of FeynCalc. The safe alternative is to use
FV.
FV[p, \[Mu]]\overline{p}^{\mu }
FVD[p, \[Mu]]p^{\mu }
FCI[FV[p, \[Mu]]] === FourVector[p, \[Mu]]\text{True}
FCI[FVD[p, \[Mu]]] === FourVector[p, \[Mu], Dimension -> D]\text{True}