An application of the parameterization method to evolution flows associated to nonautonomous systems

Abstract: Let $M$ be a finite-dimensional complete Riemannian manifold of bounded geometry. We consider a time-dependent vector field $X : \mathbb{R} \times M \to TM$ with $X_t:=X(t,\cdot) \in \mathfrak{X}<sup>r(M)$ for all $t \in \mathbb{R}$ that satisfies some further uniform continuity assumptions. We suppose that $X$ admits a globally defined integral curve $γ: \mathbb{R} \to M$. To any isolated subset $Ω$ of the Sacker-Sell spectrum of $t \mapsto \nabla X_t(γ(t))$, Sacker-Sell theory associates a subbundle $\mathscr{N}<sup>Ω$ of $T_γM$ invariant under $\nabla X_t$. Under additional nonresonance conditions on $Ω$, we prove, by an application of the parameterization method (Cabré et al., 2003), the existence of an invariant topological submanifold $\mathscr{W}^Ω\subset \mathbb{R} \times M$ with $C<sup>r$ fibers $$W_t^Ω:= \mathscr{W}^Ω\cap {t} \times M$$ that is unique in a sufficiently smooth subclass of invariant manifolds uniformly tangent to $\mathscr{N}<sup>Ω$ (made precise later). We moreover show regularity of $\mathscr{W}<sup>Ω$ with respect to parameters, and characterize the attraction towards $\mathscr{W}<sup>Ω$ via a foliation in the case $Ω$ is the slowest part of the spectrum.