Relativistic Kinetic Equations for Finite Domains and Freeze-out Problem

The relativistic kinetic equations for the two domains separated by the hypersurface with both space- and time-like parts are derived. The particle exchange between the domains separated by the time-like boundaries generates source terms and modifies the collision term of the kinetic equation. The correct hydrodynamic equations for the ``hydro+cascade'' models are obtained and their differences from existing freeze-out models of the hadronic matter are discussed.