Классификация с точностью до топологической сопряженности потоков Морса – Смейла с конечным числом модулей устойчивости на поверхностях

Известия высших учебных заведений. Прикладная нелинейная динамика. 2021. Т. 29. № 6. С. 835–850.

Kruglov V., Pochinka O.

Purpose. The purpose of this study is to consider the class of Morse-Smale flows on surfaces, to
characterize its subclass consisting of flows with a finite number of moduli of stability, and to obtain a topological
classification of such flows up to topological conjugacy, that is, to find an invariant that shows that there exists
a homeomorphism that transfers the trajectories of one flow to the trajectories of another while preserving the
direction of movement and the time of movement along the trajectories; for the obtained invariant, to construct
a polynomial algorithm for recognizing its isomorphism and to construct the realisation of the invariant by a
standard flow on the surface. Methods. Methods for finding moduli of topological conjugacy go back to the
classical works of J. Palis, W. di Melo and use smooth flow lianerization in a neighborhood of equilibrium states
and limit cycles. For the classification of flows, the traditional methods of dividing the phase surface into regions
with the same behavior of trajectories are used, which are a modification of the methods of A. A. Andronov, E.
A. Leontovich, and A. G. Mayer. Results. It is shown that a Morse-Smale flow on a surface has a finite number
of moduli if and only if it does not have a trajectory going from one limit cycle to another. For a subclass of
Morse-Smale flows with a finite number of moduli, a classification is done up to topological conjugacy by means
of an equipped graph. Conclusion. The criterion for the finiteness of the number of moduli of Morse-Smale flows
on surfaces is obtained. A topological invariant is constructed that describes the topological conjugacy class of a
Morse-Smale flow on a surface with a finite number of modules, that is, without trajectories going from one limit
cycle to another.
Keywords: Morse-Smale

Keywords: топологическая классификация, moduli of stability, поток Морса-Смейла, topological classification, Morse-Smale flow, equipped graph, оснащённый граф, модули устойчивости

Publication based on the results of: Теория динамических систем и ее приложения (2021)