∫Vn(1-∑k=1ntk)zn+1-1⁢∏k=1ntkzk-1⁢ⅆ⁡tk=Γ⁡(z1)⁢Γ⁡(z2)⁢⋯⁢Γ⁡(zn+1)Γ⁡(z1+z2+…+zn+1).