3 papers
math.GN2024
Characterizations of -compactness and realcompactness via ultrafilters in the absence of the axiom of choice
AliReza Olfati, Eliza Wajch
This article concerns the Herrlich-Chew theorem stating that a Hausdorff zero-dimensional space is -compact if and only if every clopen ultrafilter with the countable i…
math.GN2024
Quasiorders for a characterization of iso-dense spaces
Tom Richmond, Eliza Wajch
A (generalized) topological space is called an iso-dense space if the set of all its isolated points is dense in the space. The main aim of the article is to show in …
math.GN2023
A quasi-metrization theorem for hybrid topologies on the real line
Tom Richmond, Eliza Wajch
Hybrid topologies on the real line have been studied by various authors. Among the hybrid spaces, there are also Hattori spaces. However, some of the hybrid spaces are not homeomor…