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Some examples of continuous images of Radon-Nikodým compact spaces

Alexander D. Arvanitakis, Antonio Avilés (2009)

Czechoslovak Mathematical Journal

We provide a characterization of continuous images of Radon-Nikodým compacta lying in a product of real lines and model on it a method for constructing natural examples of such continuous images.

Some examples related to colorings

Michael van Hartskamp, Jan van Mill (2000)

Commentationes Mathematicae Universitatis Carolinae

We complement the literature by proving that for a fixed-point free map f : X X the statements (1) f admits a finite functionally closed cover 𝒜 with f [ A ] A = for all A 𝒜 (i.e., a coloring) and (2) β f is fixed-point free are equivalent. When functionally closed is weakened to closed, we show that normality is sufficient to prove equivalence, and give an example to show it cannot be omitted. We also show that a theorem due to van Mill is sharp: for every n 2 we construct a strongly zero-dimensional Tychonov space...

Some remarks on Radon-Nikodym compact spaces

Alexander D. Arvanitakis (2002)

Fundamenta Mathematicae

The class of quasi Radon-Nikodým compact spaces is introduced. We prove that this class is closed under countable products and continuous images. It includes the Radon-Nikodým compact spaces. Adapting Alster's proof we show that every quasi Radon-Nikodým and Corson compact space is Eberlein. This generalizes earlier results by J. Orihuela, W. Schachermayer, M. Valdivia and C. Stegall. Further the class of almost totally disconnected spaces is defined and it is shown that every quasi Radon-Nikodým...

Spaces not distinguishing convergences

Miroslav Repický (2000)

Commentationes Mathematicae Universitatis Carolinae

In the present paper we introduce a convergence condition ( Σ ' ) and continue the study of “not distinguish” for various kinds of convergence of sequences of real functions on a topological space started in [2] and [3]. We compute cardinal invariants associated with introduced properties of spaces.

Spaces not distinguishing pointwise and -quasinormal convergence

Pratulananda Das, Debraj Chandra (2013)

Commentationes Mathematicae Universitatis Carolinae

In this paper we extend the notion of quasinormal convergence via ideals and consider the notion of -quasinormal convergence. We then introduce the notion of Q N ( w Q N ) space as a topological space in which every sequence of continuous real valued functions pointwise converging to 0 , is also -quasinormally convergent to 0 (has a subsequence which is -quasinormally convergent to 0 ) and make certain observations on those spaces.

Spaces X in which all prime z -ideals of C ( X ) are minimal or maximal

Melvin Henriksen, Jorge Martinez, Grant R. Woods (2003)

Commentationes Mathematicae Universitatis Carolinae

Quasi P -spaces are defined to be those Tychonoff spaces X such that each prime z -ideal of C ( X ) is either minimal or maximal. This article is devoted to a systematic study of these spaces, which are an obvious generalization of P -spaces. The compact quasi P -spaces are characterized as the compact spaces which are scattered and of Cantor-Bendixson index no greater than 2. A thorough account of locally compact quasi P -spaces is given. If X is a cozero-complemented space and every nowhere dense zeroset...

Special almost P-spaces

Alessandro Fedeli (1997)

Commentationes Mathematicae Universitatis Carolinae

Motivated by some examples, we introduce the concept of special almost P-space and show, using the reflection principle, that for every space X of this kind the inequality “ | X | ψ c ( X ) t ( X ) " holds.

SP-scattered spaces; a new generalization of scattered spaces

Melvin Henriksen, Robert M. Raphael, Grant R. Woods (2007)

Commentationes Mathematicae Universitatis Carolinae

The set of isolated points (resp. P -points) of a Tychonoff space X is denoted by Is ( X ) (resp. P ( X ) ) . Recall that X is said to be scattered if Is ( A ) whenever A X . If instead we require only that P ( A ) has nonempty interior whenever A X , we say that X is SP-scattered. Many theorems about scattered spaces hold or have analogs for SP-scattered spaces. For example, the union of a locally finite collection of SP-scattered spaces is SP-scattered. Some known theorems about Lindelöf or paracompact scattered spaces hold also...

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