We consider a system of essentially nonlinear differential equations that does not have linear terms on the right-hand side in a neighbourhood of the rest point. Earlier, for this system, the author proved the existence of two locally integral surfaces of so-called ‘‘stable’’ and ‘‘neutral’’ types. In this article, we prove the existence of a foliation into surfaces of stable type in some neighborhood of a neutral surface under the additional assumption that the zero solution on this surface is Lyapunov uniformly stable. This result generalizes the well-known one for quasilinear systems of ODEs. Instead of assumptions on the eigenvalues of the linear approximation, we use conditions on the logarithmic norms of the Jacobi matrices of the right-hand sides. The result obtained is important for describing the behavior of integral curves of complicated systems in a neighborhood of a stationary point, for the theory of stability of solutions, for local equivalence of ODEs.
Translated title of the contributionСуществование инвариантного расслоения в окрестности локально интегральной поверхности нейтрального типа
Original languageEnglish
Pages (from-to)378-390
JournalLobachevskii Journal of Mathematics
Volume43
Issue number2
DOIs
StatePublished - 2022

    Research areas

  • essentially nonlinear differential equations, locally integral manifolds, invariant foliation, logarithmic norms, stability

ID: 103425967