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C p ( I ) is not subsequential

Viacheslav I. Malykhin (1999)

Commentationes Mathematicae Universitatis Carolinae

If a separable dense in itself metric space is not a union of countably many nowhere dense subsets, then its C p -space is not subsequential.

Cartesian closed hull for (quasi-)metric spaces (revisited)

Mark Nauwelaerts (2000)

Commentationes Mathematicae Universitatis Carolinae

An existing description of the cartesian closed topological hull of p MET , the category of extended pseudo-metric spaces and nonexpansive maps, is simplified, and as a result, this hull is shown to be a special instance of a “family” of cartesian closed topological subconstructs of p q s MET , the category of extended pseudo-quasi-semi-metric spaces (also known as quasi-distance spaces) and nonexpansive maps. Furthermore, another special instance of this family yields the cartesian closed topological hull of...

Classification of spaces of continuous functions on ordinals

Leonid V. Genze, Sergei P. Gul'ko, Tat'ana E. Khmyleva (2018)

Commentationes Mathematicae Universitatis Carolinae

We conclude the classification of spaces of continuous functions on ordinals carried out by Górak [Górak R., Function spaces on ordinals, Comment. Math. Univ. Carolin. 46 (2005), no. 1, 93–103]. This gives a complete topological classification of the spaces C p ( [ 0 , α ] ) of all continuous real-valued functions on compact segments of ordinals endowed with the topology of pointwise convergence. Moreover, this topological classification of the spaces C p ( [ 0 , α ] ) completely coincides with their uniform classification.

Classifications and characterizations of Baire-1 functions

Persephone Kiriakouli (1998)

Commentationes Mathematicae Universitatis Carolinae

Kechris and Louveau in [5] classified the bounded Baire-1 functions, which are defined on a compact metric space K , to the subclasses 1 ξ ( K ) , ξ < ω 1 . In [8], for every ordinal ξ < ω 1 we define a new type of convergence for sequences of real-valued functions ( ξ -uniformly pointwise) which is between uniform and pointwise convergence. In this paper using this type of convergence we obtain a classification of pointwise convergent sequences of continuous real-valued functions defined on a compact metric space K , and...

Closure-preserving covers in function spaces

David Guerrero Sánchez (2010)

Commentationes Mathematicae Universitatis Carolinae

It is shown that if C p ( X ) admits a closure-preserving cover by closed σ -compact sets then X is finite. If X is compact and C p ( X ) has a closure-preserving cover by separable subspaces then X is metrizable. We also prove that if C p ( X , [ 0 , 1 ] ) has a closure-preserving cover by compact sets, then X is discrete.

Compactness in the First Baire Class and Baire-1 Operators

Mercourakis, S., Stamati, E. (2002)

Serdica Mathematical Journal

For a polish space M and a Banach space E let B1 (M, E) be the space of first Baire class functions from M to E, endowed with the pointwise weak topology. We study the compact subsets of B1 (M, E) and show that the fundamental results proved by Rosenthal, Bourgain, Fremlin, Talagrand and Godefroy, in case E = R, also hold true in the general case. For instance: a subset of B1 (M, E) is compact iff it is sequentially (resp. countably) compact, the convex hull of a compact bounded subset of B1 (M,...

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