Invariant conditions of stability of unperturbed motion described by cubic differential system with quadratic part of Darboux type

Abstract

In the center-affine invariant conditions of stability of unperturbed motion, described by critical two-dimensional differential systems with quadratic nonlinearities s(1, 2), cubic nonlinearities s(1, 3) and fourth-order nonlinearities s(1, 4), were obtained.