where Λ Λ ∈ ∈ SO ⁡ ⁡ ( 1 , 3 ) and S ∈ ∈ SL ⁡ ⁡ ( 2 , C ) and S † † is the Hermitian transpose. This is used to relate the transformation properties of the differentials under a Lorentz transformation x ↦ ↦ x ′ ′ = Λ Λ x to the transformation properties of the spinors.