A λ μ ; ν = ∂ A λ μ ∂ x ν + Γ ρ ν λ A ρ μ − Γ μ ν ρ A λ ρ {\displaystyle {A^{\lambda }}_{\mu ;\nu }={\frac {\partial {A^{\lambda }}_{\mu }}{\partial {x^{\nu }}}}+\Gamma _{\rho \nu }^{\lambda }{A^{\rho }}_{\mu }-\Gamma _{\mu \nu }^{\rho }{A^{\lambda }}_{\rho }}