English

The countable type properties in free paratopological groups

Group Theory 2016-11-02 v1 General Topology

Abstract

A space XX is of countable type (resp. subcountable type) if every compact subspace FF of XX is contained in a compact subspace KK that is of countable character (resp. countable pseudocharacter) in XX. In this paper, we mainly show that: (1) For a functionally Hausdorff space XX, the free paratopological group FP(X)FP(X) and the free abelian paratopological group AP(X)AP(X) are of countable type if and only if XX is discrete; (2) For a functionally Hausdorff space XX, if the free abelian paratopological group AP(X)AP(X) is of subcountable type then XX has countable pseudocharacter. Moreover, we also show that, for an arbitrary Hausdorff μ\mu-space XX, if AP2(X)AP_{2}(X) or FP2(X)FP_{2}(X) is locally compact, then XX is homeomorphic to the topological sum of a compact space and a discrete space.

Keywords

Cite

@article{arxiv.1611.00202,
  title  = {The countable type properties in free paratopological groups},
  author = {Fucai Lin and Chuan Liu and kexiu Zhang},
  journal= {arXiv preprint arXiv:1611.00202},
  year   = {2016}
}

Comments

11 pages

R2 v1 2026-06-22T16:38:37.608Z