Displaying 781 – 800 of 1977

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Mazur spaces.

Wilansky, Albert (1981)

International Journal of Mathematics and Mathematical Sciences

Means on scattered compacta

T. Banakh, R. Bonnet, W. Kubis (2014)

Topological Algebra and its Applications

We prove that a separable Hausdor_ topological space X containing a cocountable subset homeomorphic to [0, ω1] admits no separately continuous mean operation and no diagonally continuous n-mean for n ≥ 2.

Measures on Corson compact spaces

Kenneth Kunen, Jan van Mill (1995)

Fundamenta Mathematicae

We prove that the statement: "there is a Corson compact space with a non-separable Radon measure" is equivalent to a number of natural statements in set theory.

Measure-Theoretic Characterizations of Certain Topological Properties

David Buhagiar, Emmanuel Chetcuti, Anatolij Dvurečenskij (2005)

Bulletin of the Polish Academy of Sciences. Mathematics

It is shown that Čech completeness, ultracompleteness and local compactness can be defined by demanding that certain equivalences hold between certain classes of Baire measures or by demanding that certain classes of Baire measures have non-empty support. This shows that these three topological properties are measurable, similarly to the classical examples of compact spaces, pseudo-compact spaces and realcompact spaces.

Mesocompactness and selection theory

Peng-fei Yan, Zhongqiang Yang (2012)

Commentationes Mathematicae Universitatis Carolinae

A topological space X is called mesocompact (sequentially mesocompact) if for every open cover 𝒰 of X , there exists an open refinement 𝒱 of 𝒰 such that { V 𝒱 : V K } is finite for every compact set (converging sequence including its limit point) K in X . In this paper, we give some characterizations of mesocompact (sequentially mesocompact) spaces using selection theory.

Metric-fine uniform frames

Joanne L. Walters-Wayland (1998)

Commentationes Mathematicae Universitatis Carolinae

A locallic version of Hager’s metric-fine spaces is presented. A general definition of 𝒜 -fineness is given and various special cases are considered, notably 𝒜 = all metric frames, 𝒜 = complete metric frames. Their interactions with each other, quotients, separability, completion and other topological properties are discussed.

Metrization criteria for compact groups in terms of their dense subgroups

Dikran Dikranjan, Dmitri Shakhmatov (2013)

Fundamenta Mathematicae

According to Comfort, Raczkowski and Trigos-Arrieta, a dense subgroup D of a compact abelian group G determines G if the restriction homomorphism Ĝ → D̂ of the dual groups is a topological isomorphism. We introduce four conditions on D that are necessary for it to determine G and we resolve the following question: If one of these conditions holds for every dense (or G δ -dense) subgroup D of G, must G be metrizable? In particular, we prove (in ZFC) that a compact abelian group determined by all its...

Currently displaying 781 – 800 of 1977