On the four-body problem

The four-body problem is considered using the hyperspherical basis in the momentum representation. The calculation scheme is suggested for the discrete as well as for the continuous spectrum of the four-body system with two-body potentials of arbitrary form. Recurrence relations for hyperspherical functions in the nine-dimensional space and for the coefficients of the unitary transformation of hyperspherical functions from one set of the Jacobi coordinates to another one are obtained.