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Anna Gierzkiewicz

Publications and source records attributed to Anna Gierzkiewicz.

6 recordsLinked to original sources
arXiv2024

Sharkovskii theorem for infinite dimensional dynamical systems

We present an adaptation of a relatively simple topological argument to show the existence of many periodic orbits in an infinite dimensional dynamical system, provided that the system is close to a one-dimensional map in a certain sense. Namely, we prove a Sharkovskii-type theorem: if the system has a periodic orbit of basic period $m$, then it must have all periodic orbits of periods $n \triangleright m$, for $n$ preceding $m$ in Sharkovskii ordering. The assumptions of the theorem can be verified with computer assistance, and we demonstrate the application of such an argument in the case of Delay Differential Equations (DDEs): we consider the R\"ossler ODE system perturbed by a delayed term and we show that it retains periodic orbits of all natural periods for fixed values of parameters.

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arXiv2024

No infinite spin for partial collisions converging to isolated central configurations on the plane

In the $n$-body problem, when a~cluster of bodies tends to a collision, then its normalized shape curve converges to the set of normalized central configurations, which has $SO(2)$ symmetry in the planar case. This leaves a possibility that the normalized shape curve tends to the circle obtained by rotation of some central configuration instead of a particular point on it. This is the \emph{infinite spin problem} which concerns the rotational behavior of total collision orbits in the $n$-body problem. The question also makes sense for partial collision. We show that the infinite spin is not possible if the limiting circle is isolated from other connected components of the set of normalized central configurations. Our approach extends the method from recent work for total collision by Moeckel and Montgomery, which was based on a combination of the center manifold theorem with {\L}ojasiewicz inequality. To that we add a shadowing result for pseudo-orbits near normally hyperbolic manifold and careful estimates on the influence of other bodies on the cluster of colliding bodies.

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arXiv2021

From the Sharkovskii theorem to periodic orbits for the Rössler system

We extend Sharkovskii's theorem to the cases of $N$-dimensional maps which are close to 1D maps, with an attracting $n$-periodic orbit. We prove that, with relatively weak topological assumptions, there exist also $m$-periodic orbits for all $m\triangleright n$ in Sharkovskii's order, in the nearby. We also show, as an example of application, how to obtain such a result for the Rössler system with an attracting periodic orbit, for four sets of parameter values. The proofs are computer-assisted.

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arXiv2021

A computer-assisted proof of the existence of Smale horseshoe for the folded-towel map

The paper contains a rigorous proof of existence of symbolic dynamics chaos in the generalized Hénon map's 4th iterate $H^4$, which was conjectured in the paper \textit{A 3D Smale Horseshoe in a Hyperchaotic Discrete-Time System} of Li and Yang, 2007. We prove also the uniform hyperbolicity of the invariant set with symbolic dynamics. The proofs are computer-assisted with the use of C++ library \textit{CAPD} for interval arithmetic, differentiation and integration.

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arXiv2021

Periodic orbits in Rössler system

We prove the existence of $n$-periodic orbits for almost all $n\in\mathbb{N}$ in the Rössler system with attracting periodic orbit, for two sets of parameters. The proofs are computer-assisted.

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