Equation Icon  𝜀 ( 𝜀)2 gbαoβdy(t,&tidle;s,𝜃A) = ηαβ + --gbαodβy(1)(t,𝜃A ) + -- gbBoαdβy(2)(t,𝜃A ) + O (𝜀3∕s3), (22.6 ) s s