Collectionwise normality and extensions of locally finite coverings
Collectionwise normality and fragmented collectionwise normality
Collectionwise normality and the extension of functions on product spaces
Coloring Cantor sets and resolvability of pseudocompact spaces
Let us denote by the statement that , i.e. the Baire space of weight , has a coloring with colors such that every homeomorphic copy of the Cantor set in picks up all the colors. We call a space -regular if it is Hausdorff and for every nonempty open set in there is a nonempty open set such that . We recall that a space is called feebly compact if...
Combinatorics of open covers (III): games, Cp (X)
Some of the covering properties of spaces as defined in Parts I and II are here characterized by games. These results, applied to function spaces of countable tightness, give new characterizations of countable fan tightness and countable strong fan tightness. In particular, each of these properties is characterized by a Ramseyan theorem.
Combinatorics of open covers (VII): Groupability
We use Ramseyan partition relations to characterize: ∙ the classical covering property of Hurewicz; ∙ the covering property of Gerlits and Nagy; ∙ the combinatorial cardinal numbers and add(ℳ ). Let X be a -space. In [9] we showed that has countable strong fan tightness as well as the Reznichenko property if, and only if, all finite powers of X have the Gerlits-Nagy covering property. Now we show that the following are equivalent: 1. has countable fan tightness and the Reznichenko property. 2....
Compact and extremally disconnected spaces.
Compact Hausdorff spaces with two open sets
Compact Hausdorff spaces with two or three types of open subspaces:new results and open questions
Compact minimalization of inverse systems
Compact objects surjectivity of epimorphisms and compactifications
Compact sets without converging sequences in the random real model.
Compact spaces homeomorphic to a ray of ordinals
Compact spaces that do not map onto finite products
We provide examples of nonseparable compact spaces with the property that any continuous image which is homeomorphic to a finite product of spaces has a maximal prescribed number of nonseparable factors.
Compact unions of closed subsets are closed and compact intersections of open subsets are open
Compacta are maximally -resolvable
It is well-known that compacta (i.e. compact Hausdorff spaces) are maximally resolvable, that is every compactum contains many pairwise disjoint dense subsets, where denotes the minimum size of a non-empty open set in . The aim of this note is to prove the following analogous result: Every compactum contains many pairwise disjoint -dense subsets, where denotes the minimum size of a non-empty set in .
Compactification and compactoidification
Compactification and the continuum hypothesis
Compactification of pointed 1-movable spaces
Compactification of Products