Statistical theory of gravity and capillary waves on the surface of a finite-depth fluid

In many physical situations, the oscillations of the free surface of a fluid are a random process in space and time. This is equally correct for ripples in a tea cup as well as for large ocean waves. In both cases, the situation must be described by the averaged equations imposed on a certain set of correlation functions. The derivation of such equations is not a simple problem even on a `physical' level of rigor. It is especially important to determine correctly the conditions of applicability for a given statistical description. For some physical reasons they might happen to be narrow. In this context, the statistical description of potential surface waves on the surface of an ideal fluid of finite depth is described.