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Some questions of Arhangel'skii on rotoids

Harold Bennett, Dennis Burke, David Lutzer (2012)

Fundamenta Mathematicae

A rotoid is a space X with a special point e ∈ X and a homeomorphism F: X² → X² having F(x,x) = (x,e) and F(e,x) = (e,x) for every x ∈ X. If any point of X can be used as the point e, then X is called a strong rotoid. We study some general properties of rotoids and prove that the Sorgenfrey line is a strong rotoid, thereby answering several questions posed by A. V. Arhangel'skii, and we pose further questions.

Some results and problems about weakly pseudocompact spaces

Oleg Okunev, Angel Tamariz-Mascarúa (2000)

Commentationes Mathematicae Universitatis Carolinae

A space X is truly weakly pseudocompact if X is either weakly pseudocompact or Lindelöf locally compact. We prove: (1) every locally weakly pseudocompact space is truly weakly pseudocompact if it is either a generalized linearly ordered space, or a proto-metrizable zero-dimensional space with χ ( x , X ) > ω for every x X ; (2) every locally bounded space is truly weakly pseudocompact; (3) for ω < κ < α , the κ -Lindelöfication of a discrete space of cardinality α is weakly pseudocompact if κ = κ ω .

Spaces of continuous characteristic functions

Raushan Z. Buzyakova (2006)

Commentationes Mathematicae Universitatis Carolinae

We show that if X is first-countable, of countable extent, and a subspace of some ordinal, then C p ( X , 2 ) is Lindelöf.

Spaces of continuous step functions over LOTS

Raushan Z. Buzyakova (2006)

Fundamenta Mathematicae

We investigate spaces C p ( · , n ) over LOTS (linearly ordered topological spaces). We find natural necessary conditions for linear Lindelöfness of C p ( · , n ) over LOTS. We also characterize countably compact LOTS whose C p ( · , n ) is linearly Lindelöf for each n. Both the necessary conditions and the characterization are given in terms of the topology of the Dedekind completion of a LOTS.

Splittability for ordered topological spaces

Dermot J. Marron, T. Brian M. McMaster (2000)

Bollettino dell'Unione Matematica Italiana

In quest'articolo dimostriamo come il concetto «spezzabilità», formulato e sviluppato di Arhangel'skii, viene trasferito dallo studio di spazi topologici a quello di spazi topologici parzialmente ordinati. Otteniamo numerosi risultati in forma «se X è spezzabile (facendo uso di funzioni appropriatamente scelte) su spazi che hanno una proprietà, allora anche X soddisfa la stessa proprietà».

The Gruenhage property, property *, fragmentability, and σ-isolated networks in generalized ordered spaces

Harold Bennett, David Lutzer (2013)

Fundamenta Mathematicae

We examine the Gruenhage property, property * (introduced by Orihuela, Smith, and Troyanski), fragmentability, and the existence of σ-isolated networks in the context of linearly ordered topological spaces (LOTS), generalized ordered spaces (GO-spaces), and monotonically normal spaces. We show that any monotonically normal space with property * or with a σ-isolated network must be hereditarily paracompact, so that property * and the Gruenhage property are equivalent in monotonically normal spaces....

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