English

More absorbers in hyperspaces

General Topology 2017-04-25 v1

Abstract

The family of all subcontinua that separate a compact connected nn-manifold XX (with or without boundary), n3n\ge 3, is an FσF_\sigma-absorber in the hyperspace C(X)C(X) of nonempty subcontinua of XX. If D2(Fσ)D_2(F_\sigma) is the small Borel class of spaces which are differences of two σ\sigma-compact sets, then the family of all (n1)(n-1)-dimensional continua that separate XX is a D2(Fσ)D_2(F_\sigma)-absorber in C(X)C(X). The families of nondegenerate colocally connected or aposyndetic continua in InI^n and of at least two-dimensional or decomposable Kelley continua are FσδF_{\sigma\delta}-absorbers in the hyperspace C(In)C(I^n) for n3n\ge 3. The hyperspaces of all weakly infinite-dimensional continua and of CC-continua of dimensions at least 2 in a compact connected Hilbert cube manifold XX are Π11\Pi ^1_1-absorbers in C(X)C(X). The family of all hereditarily infinite-dimensional compacta in the Hilbert cube IωI^\omega is Π11\Pi ^1_1-complete in 2Iω2^{I^\omega}.

Keywords

Cite

@article{arxiv.1606.06102,
  title  = {More absorbers in hyperspaces},
  author = {Paweł Krupski and Alicja Samulewicz},
  journal= {arXiv preprint arXiv:1606.06102},
  year   = {2017}
}
R2 v1 2026-06-22T14:29:18.425Z