Formula_7771

\[\varphi=\sum_{l \geqslant 0} \frac{1}{l !} \sum_{i_{1}, i_{2}, \ldots, i_{l}=1} \sum_{j} e_{j} x_{j}^{i_{1}} x_{j}^{i_{2}} \ldots x_{j}^{i_{l}} \frac{\partial^{l}}{\partial X^{i_{\partial}} \partial X^{i_{1}} \ldots \partial X^{i_{l}}} \frac{1}{\left|R_{0}\right|},\left(^{*}\right)\]