English

Quotients of $\mathbb{N}^*$, $\omega$-limit sets, and chain transitivity

Dynamical Systems 2019-04-23 v2 General Topology

Abstract

N=βNN\mathbb{N}^* = \beta\mathbb{N} \setminus \mathbb{N} has a canonical dynamical structure provided by the shift map, the unique continuous extension to βN\beta\mathbb{N} of the map nn+1n \mapsto n+1 on N\mathbb{N}. Here we investigate the question of what dynamical systems can be written as quotients of N\mathbb{N}^*. We prove that a dynamical system is a quotient of N\mathbb{N}^* if and only if it is isomorphic to the ω\omega-limit set of some point in some larger system. This provides a full external characterization of the quotients of N\mathbb{N}^*. We also prove, assuming MAσ-centered(κ)_{\sigma\text{-centered}}(\kappa), that a dynamical system of weight κ\kappa is a quotient of N\mathbb{N}^* if and only if it is chain transitive. This provides a consistent partial internal characterization of the quotients of N\mathbb{N}^*, and a full internal characterization for metrizable systems.

Keywords

Cite

@article{arxiv.1501.00157,
  title  = {Quotients of $\mathbb{N}^*$, $\omega$-limit sets, and chain transitivity},
  author = {William R. Brian},
  journal= {arXiv preprint arXiv:1501.00157},
  year   = {2019}
}

Comments

This paper was made obsolete by a later paper