# Prime Ends Dynamics in Parametrised Families of Rotational Attractors

## TL;DR

This paper explores complex boundary dynamics of invariant domains on the 2-sphere, constructing examples with multiple attractors and rotation numbers, advancing understanding of topological and dynamical properties in parametrized families.

## Contribution

It introduces new examples of rotational attractors with complex boundary dynamics, answering open questions and extending previous theoretical results in sphere dynamics.

## Key findings

- Existence of Lakes of Wada rotational attractors close to identity
- Construction of parametrized Birkhoff-like cofrontier attractors with multiple rotation numbers
- Demonstration of non-transitive Birkhoff-like attractors with specific prime ends rotation properties

## Abstract

We provide several new examples in dynamics on the $2$-sphere, with the emphasis on better understanding the induced boundary dynamics of invariant domains in parametrized families. First, motivated by a topological version of the Poincar\'e-Bendixson Theorem obtained recently by Koropecki and Passeggi, we show the existence of homeomorphisms of $\mathbb{S}^2$ with Lakes of Wada rotational attractors, with an arbitrarily large number of complementary domains, and with or without fixed points, that are arbitrarily close to the identity. This answers a question of Le Roux. Second, from reduced Arnold's family we construct a parametrised family of Birkhoff-like cofrontier attractors, where at least for uncountably many choices of the parameters, two distinct irrational prime ends rotation numbers are induced from the two complementary domains. This example complements the resolution of Walker's Conjecture by Koropecki, Le Calvez and Nassiri from 2015. Third, answering a question of Boyland, we show that there exists a non-transitive Birkhoff-like attracting cofrontier which is obtained from a BBM embedding of inverse limit of circles, such that the interior prime ends rotation number belongs to the interior of the rotation interval of the cofrontier dynamics. There exists another BBM embedding of the same attractor so that the two induced prime ends rotation numbers are exactly the two endpoints of the rotation interval.