Formula_3540

\[\begin{gathered}L(\varphi \exp \{i \lambda S\})=\exp \{i \lambda S\} \sum_{j=0}^{\infty}(i \lambda)^{-j}\left(R_{j} \varphi\right)(x), \\R_{0} \varphi=L^{0} \varphi, \quad R_{1} \varphi=\left(\frac{\partial L^{0}}{\partial \xi}, \frac{\partial \varphi}{\partial x}\right)+\frac{1}{2} \operatorname{Sp}\left(\frac{\partial^{2} L^{0}}{\partial \xi^{2}}, \frac{\partial^{2} S}{\partial x^{2}}\right) \varphi,\end{gathered}\]