On topological groups containing a Fréchet-Urysohn fan

Author
T. Banakh
Department of Mathematics, Lviv University, Universytetska 1,Lviv, 290602, Ukraine
Abstract
Suppose $G$ is a topological group containing a (closed) topological copy of the Fréchet-Urysohn fan. If $G$ is a perfectly normal sequential space (a normal $k$-space) then every closed metrizable subset in $G$ is locally compact. Applying this result to topological groups whose underlying topological space can be written as the direct limit of a sequence of closed metrizable subsets, we get that every such a group either is metrizable or is homeomorphic to the product of a $k_\omega$-space and a discrete space.
Keywords
topological group, Fréchet-Urysohn fan, perfectly normal sequential space, normal k-space, closed metrizable subset, locally compact, direct limit
DOI
doi:10.30970/ms.9.2.149-154
Reference
1. E. Pentsak On manifolds modeled on direct limits of $C$-universal ANR's// Matematychni Studii V.5 -- 1995 p. 107--116

Pages
149-154
Volume
9
Issue
2
Year
1998
Journal
Matematychni Studii
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