University of Wollongong
Browse

Local compactness in free topological groups

Download (1.28 MB)
journal contribution
posted on 2024-11-15, 05:30 authored by Peter NickolasPeter Nickolas, Mikhail Tkachenko
We show that the subspace An(X) of the free Abelian topological group A(X) on a Tychonoff space X is locally compact for each n ω if and only if A2(X) is locally compact if an only if F2(X) is locally compact if and only if X is the topological sum of a compact space and a discrete space. It is also proved that the subspace Fn(X) of the free topological group F(X) is locally compact for each n ω if and only if F4(X) is locally compact if and only if Fn(X) has pointwise countable type for each n ω if and only if F4(X) has pointwise countable type if and only if X is either compact or discrete, thus refining a result by Pestov and Yamada. We further show that An(X) has pointwise countable type for each n ω if and only if A2(X) has pointwise countable type if and only if F2(X) has pointwise countable type if and only if there exists a compact set C of countable character in X such that the complement X \ C is discrete. Finally, we show that F2(X) is locally compact if and only if F3(X) is locally compact, and that F2(X) has pointwise countable type if and only if F3(X) has pointwise countable type.

History

Citation

Nickolas, P. & Tkachenko, M. (2003). Local compactness in free topological groups. Bulletin of the Australian Mathematical Society, 68 (2), 243-265.

Journal title

BULLETIN OF THE AUSTRALIAN MATHEMATICAL SOCIETY

Volume

68

Issue

2

Pagination

243-265

Language

English

RIS ID

6922

Usage metrics

    Categories

    Exports

    RefWorks
    BibTeX
    Ref. manager
    Endnote
    DataCite
    NLM
    DC