Formula_10029

\[\frac{\partial}{\partial \tau} T_{\tau}\left(y_{3} \mid y_{1}\right)=\int\left\{W\left(y, y^{\prime}\right) T_{\tau}\left(y^{\prime}, t\right)-W\left(y^{\prime} \mid y\right) T_{\tau}(y, t)\right\} d y^{\prime} .\]