A note on Fréchet spaces
A note on maximally resolvable spaces.
A note on Rudin's example of Dowker space
A note on separability of the Fell-hyperspace topology
A perfectly normal locally metrizable non-paracompact space
A solution to Comfort's question on the countable compactness of powers of a topological group
In 1990, Comfort asked Question 477 in the survey book “Open Problems in Topology”: Is there, for every (not necessarily infinite) cardinal number , a topological group G such that is countably compact for all cardinals γ < α, but is not countably compact? Hart and van Mill showed in 1991 that α = 2 answers this question affirmatively under . Recently, Tomita showed that every finite cardinal answers Comfort’s question in the affirmative, also from . However, the question has remained...
A tiny peculiar Fréchet space
A topological characterization of stationary sets
A topological property of beta(N).
A uniquely homogeneous space need not be a topological group
AC holds iff every compact completely regular topology can be extended to a compact Tychonoff topology
We show that AC is equivalent to the assertion that every compact completely regular topology can be extended to a compact Tychonoff topology.
Adequate families of sets and function spaces
Algunas propiedades del ejemplo de Tychonoff de un espacio regular que no es completamente regular.
Algunos resultados sobre anillos de Wallman.
An atriodic tree-like continuum with positive span which admits a monotone mapping to a chainable continuum
An example for mappings related to confluence
Confluence of a mapping between topological spaces can be defined by several ways. J.J. Charatonik asked if two definitions of the confluence using the components and quasi-components are equivalent for surjective mappings with compact point inverses. We give the negative answer to this question in Example 2.1.
An example for mappings related to semi-confluence.
An example of a non-compact locally compact arcwise connected metric space with the fixed point property
Application on local discrete expansion.
Base-base paracompactness and subsets of the Sorgenfrey line
A topological space is called base-base paracompact (John E. Porter) if it has an open base such that every base has a locally finite subcover . It is not known if every paracompact space is base-base paracompact. We study subspaces of the Sorgenfrey line (e.g. the irrationals, a Bernstein set) as a possible counterexample.