C-embedding and P-embedding in subspaces of products of ordinals

Nobuyuki Kemoto, Toshimichi Usuba

Research output: Contribution to journalArticlepeer-review

Abstract

It is known that in X=A×B, where A and B are subspaces of ordinals, all closed C-embedded subspaces of X are P-embedded. Also it is asked whether all closed C-embedded subspaces of X are P-embedded whenever X is a subspace of products of two ordinals. In this paper, we prove that both of the following are consistent with ZFC: • there is a subspace X of (ω+1)×ω1 such that the closed subspace X∩({ω}×ω1) is C-embedded in X but not P-embedded in X, • for every subspace X of (ω+1)×ω1, if the closed subspace X∩({ω}×ω1) is C-embedded in X, then it is P-embedded in X.

Original languageEnglish
Article number108194
JournalTopology and its Applications
Volume318
DOIs
Publication statusPublished - 2022 Aug 15

Keywords

  • 2<2
  • Almost disjoint family
  • C-embedding
  • Consistent
  • Independent family
  • P-embedding
  • Subspaces of products of ordinals

ASJC Scopus subject areas

  • Geometry and Topology

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