Formula_4175

\[\rho_{\lambda}(x)_{m}=\xi^{-1}(\Lambda, z, \beta) \sum_{n=0}^{\infty} \frac{z^{n+m}}{n !} \int_{\Lambda^{n}} d x_{m+1} \ldots d x_{m+n} e^{-\beta U(x)_{m+n}}\]