Equation Icon  μ1ν1μ2ν2⋅⋅⋅μN νN -1- A1A2⋅⋅⋅AN B1B2⋅⋅⋅BN μ1ν1 μ2ν2 μN νN Q = N !𝜖 𝜖 f A1B1f A2B2 ⋅⋅⋅f ANBN . (220 )