Equation Icon  1( ) 1 1 --gacgbd − gabgcd ∂gab∂gcd + ---F tabcFtabc + --N 2F abcdFabcd = 0, (10.5 ) 4 12 48 1N F tbcdF = 0, (10.6 ) 6 abcd É›tabc1c2c3c4d1d2d3d4Fc c cc Fd dd d = 0, (10.7 ) 1 23 4 1 23 4