Equation Icon  ∫ 3 ∘ --------- ∫ S = − TM2 d σ − det 𝒢μν + TM2 𝒜3, (136 ) a b A M A 𝒢μν = E μ(X, 𝜃)Eν(X, 𝜃)ηab, E μ ≡ ∂μZ E M (X, 𝜃), 1 μνρ B C D 𝒜3 = 3!𝜀 E μ E ν E ρ ABCD (X, 𝜃).