English

Connectedness modulo a topological property

General Topology 2015-06-26 v2

Abstract

Let P{\mathscr P} be a topological property. We say that a space XX is P{\mathscr P}-connected if there exists no pair CC and DD of disjoint cozero-sets of XX with non-P{\mathscr P} closure such that the remainder X\(CD)X\backslash(C\cup D) is contained in a cozero-set of XX with P{\mathscr P} closure. If P{\mathscr P} is taken to be "being empty" then P{\mathscr P}-connectedness coincides with connectedness in its usual sense. We characterize completely regular P{\mathscr P}-connected spaces, with P{\mathscr P} subject to some mild requirements. Then, we study conditions under which unions of P{\mathscr P}-connected subspaces of a space are P{\mathscr P}-connected. Also, we study classes of mappings which preserve P{\mathscr P}-connectedness. We conclude with a detailed study of the special case in which P{\mathscr P} is pseudocompactness. In particular, when P{\mathscr P} is pseudocompactness, we prove that a completely regular space XX is P{\mathscr P}-connected if and only if clβX(βX\υX)cl_{\beta X}(\beta X\backslash\upsilon X) is connected, and that P{\mathscr P}-connectedness is preserved under perfect open continuous surjections. We leave some problems open.

Keywords

Cite

@article{arxiv.1205.5203,
  title  = {Connectedness modulo a topological property},
  author = {M. R. Koushesh},
  journal= {arXiv preprint arXiv:1205.5203},
  year   = {2015}
}

Comments

12 pages

R2 v1 2026-06-21T21:08:32.584Z