Non-degenerate systems and generic properties of the integrable Hamiltonian systems

The goal of the paper is to clarify whether the non-degenerate Hamiltinian systems are “typical” among all integrable systems. The importance of this problem is emphasized by a theorem of Fomenko–Zieschang, in which an isoenergy invariant determining the nondegenerate systems up to topological equivalence is constructed. Bibl. 12 titles.