Equation Icon  di∑m𝔞3 ∑ mu∑ltα [ ][ ] ℒ 𝒰 ∕𝒦(𝒰 ) = ∂xφ (i)(x )∂x φ(i)(x) + e2α(φ) ∂x χ(α)(x) + ⋅⋅⋅ ∂xχ (α) (x ) + ⋅⋅⋅ , (7.8 ) 3 3 i=1 +s =1 [sα] [sα] α∈Σ α