Equation Icon  /\ab = N ab[h ,h ] + N ab[h ,h ] + N ab[h 2 ,h ] + N ab[h ,h 2] (M2Mab) (M) (MMab) (MMab) (M) (M ) (Mab) (Mab) (M ) + M ab[h(M),h(M),h(Mab)] + M ab[h(M),h(Mab),h(M)] + M ab[h(Mab),h(M),h(M)] (111)