Persistence of normally expanded submanifolds with boundary or corners

A geometrical proof of the persistence of normally hyperbolic submanifolds

We present a simple, computation free and geometrical proof of the following classical result: for a diffeomorphism of a manifold, any compact submanifold which is invariant and normally hyperbolic persists under small perturbations of the diffeomorphism. The persistence of a Lipschitz invariant submanifold follows from an application of the Schauder fixed point theorem to a graph transform, while smoothness and uniqueness of the invariant submanifold are obtained through geometrical arguments. Moreover, our proof provides a new result on persistence and regularity of "topologically" normally …

Persistence of noncompact normally hyperbolic invariant manifolds in bounded geometry

We prove a persistence result for noncompact normally hyperbolic invariant manifolds in the setting of Riemannian manifolds of bounded geometry. Bounded geometry of the ambient manifold is a crucial assumption required to control the uniformity of all estimates throughout the proof. The $C^{k,α}$-smoothness result is optimal with respect to the spectral gap condition involved. The core of the persistence proof is based on the Perron method. In the process we derive new results on noncompact submanifolds in bounded geometry: a uniform tubular neighborhood theorem and uniform smooth approximatio…

An inclination lemma for normally hyperbolic manifolds with an application to diffusion

Let ($M$, $Ω$) be a smooth symplectic manifold and $f:M\rightarrow M$ be a symplectic diffeomorphism of class $C^l$ ($l\geq 3$). Let $N$ be a compact submanifold of $M$ which is boundaryless and normally hyperbolic for $f$. We suppose that $N$ is controllable and that its stable and unstable bundles are trivial. We consider a $C^1$-submanifold $\d$ of $M$ whose dimension is equal to the dimension of a fiber of the unstable bundle of $T_NM$. We suppose that $\d$ transversely intersects the stable manifold of $N$. Then, we prove that for all $\varepsilon>0$, and for $n$ $\in$ $\N$ large enough, …

Persistence of stratification of normally expanded laminations

This manuscript complements the Hirsch-Pugh-Shub (HPS) theory on persistence of normally hyperbolic laminations and the theorem of Robinson on the structural stability of diffeomorphisms that satisfy Axiom A and the strong transversality condition (SA). We generalize these results by introducing a geometric object: the stratification of laminations. It is a stratification whose strata are laminations. Our main theorem implies the persistence of some stratifications whose strata are normally expanded. The dynamics is a $C^r$-endomorphism of a manifold (which is possibly not invertible). The per…

Reverse-engineering invariant manifolds with asymptotic phase

We present a recipe for rendering a submanifold normally hyperbolic and invariant within a stability basin. The construction includes the ability to choose the asymptotic phase map. We are motivated by the notion of "templates and anchors" -- the biomechanical observation that animal motions are often governed by low dimensional dynamics -- and the growing applications in robotics which desire means for making such biologically derived templates govern the dynamics of robots. Our approach is fairly universal, in the sense that a broad range of model reduction constructions must be normally hyp…

将离散几何奇异摄动理论扩展到非双曲点

Extending Discrete Geometric Singular Perturbation Theory to Non-Hyperbolic Points

本文利用Takens嵌入定理将离散几何奇异摄动理论扩展到非正规双曲区域，证明快慢映射在非双曲奇点附近的动力学可由相应快慢向量场的时间1映射局部逼近，并应用于折叠、跨临界、叉形等奇点及中心流形分析。