In general, given four quantities A and Z = (Z x, Z y, Z z) and their Lorentz-boosted counterparts A ′ and Z ′ = (Z ′ x, Z ′ y, Z ′ z), a relation of the form A 2 − − Z ⋅ ⋅ Z = A ′ 2 − − Z ′ ⋅ ⋅ Z ′ implies the quantities transform under Lorentz transformations similar to the transformation of spacetime coordinates; A ′ = γ γ ( A − − v n ⋅ ⋅ Z c ) , Z ′ = Z + ( γ γ − − 1 ) ( Z ⋅ ⋅ n ) n − − γ γ A v n c .