equation icon  [ 1 1 ] eaa = dba + -s2ab(t)aa(t) + --s2Rba0c(t)wc + O(s3) eab [ 2( ) 2 ] 1 b 1 2 1 2 b 3 a + - s 1 - -sabw aa(t) + -s aa(t)- -s Ra0b0(u)w + O(s ) e0. (227) 2 2 2