Equation Icon  αβ 1 (α β) ε′( α′ β′ α′ β′) ι′ 2 U γ′δ′;ε = -g α′g β′g ε R γ′ε′ι′δ δ′ + R δ′ε′ι′δ γ′ σ + 𝒪 (λ ), (359 ) 2 ( ) U αβ′ ′′ = 1g (α′gβ)′ R αγ′′ε′ι′δβ′′ + R α′δ′ε′ι′δβ′′ σ ι′ + 𝒪(λ2), (360 ) γ δ;ε 2 α β δ γ