Classification of integrable Hamiltonian systems with nondegenerate singularities on \(\mathbb {C}P^{2}\)
From the text: ``This paper studies topological properties of the sets of singular points of integrable Hamiltonian systems with two degrees of freedom. In the case where all singularities of the system are nondegenrate, this set is a union of immersed 2-submanifolds and isolated singular points of type focus-focus. It is proved that the submanifolds filled by hyperbolic singularities have trivial normal bundle in the phase space of the system. In particular, this makes it possible to describe all systems with nondegenerate singularities on the complex projective plane.''
scientific article; zbMATH DE number 5998369