A shadowable chain recurrent set with an attached hyperbolic singularity
Sogo Murakami
TL;DR
The paper addresses whether chain recurrent sets that contain an attached hyperbolic singularity can exhibit the standard shadowing property. It builds a $C^\infty$ flow on $S^4$ whose nonwandering/chain recurrent set contains such an attached singularity, yet retains standard shadowing on the chain recurrent set by modeling a factor of a modified suspension flow of a Smale horseshoe. A central tool is a factor transfer theorem (Theorem \ref{'thm.factor'}) that carries standard shadowing from a model flow to its quotient when a closed orbit is collapsed to a singularity. By wiring the model through a carefully constructed $X$ on $\mathbb{R}^4$ and a projection to $S^4$, the authors obtain a counterexample to a conjecture of Arbieto, López, Rego and Sánchez, showing that shadowing can persist in the presence of attached singularities. The work advances understanding of shadowing in nonuniformly hyperbolic dynamics and provides a method to generate flows with shadowing on ${\rm CR}$ sets containing singularities.
Abstract
We prove that every factor map between topological flows preserves the standard shadowing property if it is injective except for a closed orbit that shrinks to a singularity. As an application, we construct a $C^\infty$-flow on a four-dimensional sphere whose nonwandering set contains an attached hyperbolic singularity yet possesses the standard shadowing property. This gives a counterexample to a conjecture given by Arbieto, López, Rego and Sánchez (Math. Annalen 390:417-437).
