Equation Icon  [ ( ) ] gtt = − 1 + 2aayˆa + aayˆa 2 + R0c0dˆycˆyd + O (s3) , (9.18 ) 2- c d 3 gta = − 3 R0cadˆy ˆy + O(s ), (9.19 ) g = δ (1 − R ˆycˆyd) + O (s3). (9.20 ) ab ab 0c0d