Equation 13.13.392263D1F9CA2F

\begin{equation} \int _{\{ \varphi \leq \phi -k \} } \theta _{\varphi _ j}^ n=\int _ X \theta _{\varphi _ j}^ n-\int _{\{ \varphi >\phi -k \} } \theta _{\varphi _ j}^ n=\int _ X \theta _{\phi }^ n-\int _{\{ \varphi >\phi -k \} } \theta _{\varphi }^ n, \end{equation}