Formula_3486

\[\left.\begin{array}{l}\frac{\partial}{\partial t} f_{1}(\varepsilon ; t)=\int_{\varepsilon}^{\infty} d \varepsilon^{\prime}\left(w_{1}+w_{3}\right)\left(\varepsilon^{\prime}, \varepsilon\right) f_{1}\left(\varepsilon^{\prime} ; t\right)- \\-f_{1}(\varepsilon ; t) \int_{0}^{\varepsilon} d \varepsilon^{\prime}\left(w_{1}+w_{3}\right)\left(\varepsilon, \varepsilon^{\prime}\right)+2 \int_{\varepsilon}^{\infty} d \varepsilon^{\prime} f_{2}\left(\varepsilon^{\prime} ; t\right) w_{2}\left(\varepsilon^{\prime}, \varepsilon\right), \\\frac{\partial}{\partial t} f_{2}(\varepsilon ; t)=\int_{\varepsilon}^{\infty} d \varepsilon^{\prime} f_{1}\left(\varepsilon^{\prime}, t\right) w_{1}\left(\varepsilon^{\prime}, \varepsilon^{\prime}-\varepsilon\right)- \\-f_{2}(\varepsilon ; t) \int_{0}^{\varepsilon} d \varepsilon^{\prime} w_{2}\left(\varepsilon^{\prime}, \varepsilon\right) .\end{array}\right\}\]