Equation Icon  ⌊ ⌋ ⌊ ⌋ ∑ ∑ ∂μV2 (x)V2(x)− 1 = ∂ μExp ⌈ χα (x )Eα⌉ Exp ⌈− χα′(x)E α′⌉ α∈Δ α ′∈Δ + + = ∑ ∂ χ (x)E + 1- ∑ χ (x)∂ χ ′(x )[E ,E ′] μ α α 2! ′ α μ α α α α∈Δ+ α,α∈Δ+ -1 ∑ + 3! χα(x )χα′(x )∂μχα′′(x)[E α,[E α′,Eα′′]] + ⋅⋅⋅ . (9.62 ) α,α′,α′′∈Δ+