English

Continuous selections, prime number and a covering type property

General Topology 2020-04-21 v1

Abstract

Let (X,τ)(X,\tau) be a Hausdorff space and nωn\in\omega. We prove that if XX admits a continuous selection over Fn(X)\mathcal{F}_{n}(X) (nonempty subsets of XX of cardinality at most nn), then for every nm2nn\leq m\leq 2n such that mm is not a prime number, XX admits a continuous selection over [X]m[X]^m (subsets of XX of cardinality mm). As a consequence of this, a space XX admits a continuous selection for every natural number if and only if the same is true for every prime number. For Hausdorff spaces (X,τ)(X,\tau) which admit continuous selections over [X]2[X]^2, we characterize the existence of continuous selections over [X]n[X]^n for n2n\geq 2, in terms of a covering-type property.

Keywords

Cite

@article{arxiv.2004.08496,
  title  = {Continuous selections, prime number and a covering type property},
  author = {Jorge Antonio Cruz Chapital},
  journal= {arXiv preprint arXiv:2004.08496},
  year   = {2020}
}
R2 v1 2026-06-23T14:55:55.780Z