In this note we study a function which frequently appears in partial differential equations. We prove that this function is absolutely continuous, hence it can be written as a definite integral. As a result we obtain some estimates regarding solutions of the Hamilton-Jacobi systems.
Amin Farjudian's work on this article has been partially supported by the Natural Science Foundation of China (Grant No. 61070023) and Ningbo Natural Science Programme by Ningbo S&T bureau (Grant No. 2010A610104).