Equation Icon  ( ) U αβ′;γ = 1-gγγ′ gαα′R α′β′γ′δ′ − 1g αβ′R γ′δ′ σδ′ + O (λ2), (15.11 ) 2 ( 3 ) α 1- α α′ 1- α δ′ 2 U β′;γ′ = 2 g α′R β′γ′δ′ + 3 gβ′R γ′δ′ σ + O (λ ), (15.12 )