Equation Icon  [ ] β′ γ′ β′ α′ 1 b 1 ( b) 2 Uαβ′;γ′u u + U αβ′a = g α aα′ + -rR α′0b0Ω − -r R00 + R0b Ω uα′ + O(r ) (18.17 ) 2 6