English

Ideal Analytic sets

Logic 2026-03-09 v4 General Topology

Abstract

The aim of this paper is to give natural examples of Σ11\mathbf{\Sigma}_1^1-complete and Π11\mathbf{\Pi}_1^1-complete sets. In the first part, we consider ideals on ω\omega. In particular, we show that the Hindman ideal H\mathcal{H} is Π11\mathbf{\Pi}_1^1-complete and consider a number of ideals generated in the similar fashion. Moreover, we show that the ideal D\mathcal{D} is also Π11\mathbf{\Pi}_1^1-complete. In the second part, we focus on families of trees (on ω\omega and 22) containing a specific tree type. We show the connection between two topics and explore some classical tree types (like Sacks and Miller).

Keywords

Cite

@article{arxiv.2310.07693,
  title  = {Ideal Analytic sets},
  author = {Łukasz Mazurkiewicz and Szymon Żeberski},
  journal= {arXiv preprint arXiv:2310.07693},
  year   = {2026}
}

Comments

13 pages

R2 v1 2026-06-28T12:47:40.179Z