English

Classification of saddle-focus singularities

Differential Geometry 2023-01-26 v1 Symplectic Geometry

Abstract

The paper presents an algorithm for topological classification of nondegenerate saddle-focus singularities of integrable Hamiltonian systems with three degrees of freedom up to semi-local equivalence. In particular, we prove that any singularity of saddle-focus type can be represented as an almost direct product in which the acting group is cyclic. Based on the constructed algorithm, a complete list of singularities of saddle-focus type of complexity 11, 22, and 33, i.e., singularities whose leaf contains one, two, or three singular points of rank 00, is obtained. Earlier both singularities of saddle-focus type of complexity 11 were also described by L.M. Lerman.

Keywords

Cite

@article{arxiv.2301.10298,
  title  = {Classification of saddle-focus singularities},
  author = {I. K. Kozlov and A. A. Oshemkov},
  journal= {arXiv preprint arXiv:2301.10298},
  year   = {2023}
}
R2 v1 2026-06-28T08:19:05.695Z