With these general forms one obtains the propagators in unitary gauge for λ = 0, the propagator in Feynman or 't Hooft gauge for λ = 1 and in Landau or Lorenz gauge for λ = ∞. There are also other notations where the gauge parameter is the inverse of λ, usually denoted ξ (see R ξ gauges). The name of the propagator, however, refers to its final form and not necessarily to the value of the gauge parameter.