One- and two-particle wave functions of multihadron systems

One- and two-particle wave functions of systems of several hadrons (and, possibly, partons) that determine the amplitudes for the production of such systems in hard processes in the case when the invariant mass of the system is much less than the characteristic momentum transfer are introduced. The wave functions of multihadron systems are calculated in terms of the wave functions of the hadrons in them in the case when these hadrons are sufficiently well separated from each other (and from the partons) in the phase space.