On the Fréchet-Urysohn property in spaces of continuous functions
On the fundamental dimension of approximatively 1-connected compacta
On the inverse image of Baire spaces.
On the -Baire property
In this note we show the following theorem: “Let be an almost -discrete space, where is a regular cardinal. Then is -Baire iff it is a -Baire space and every point- open cover of such that is locally- at a dense set of points.” For we obtain a well-known characterization of Baire spaces. The case is also discussed.
On the lattice structure of topologies
On the level spaces of fuzzy topological spaces.
On the Lindelöf property of spaces of continuous functions over a Tychonoff space and its subspaces
We study relations between the Lindelöf property in the spaces of continuous functions with the topology of pointwise convergence over a Tychonoff space and over its subspaces. We prove, in particular, the following: a) if is Lindelöf, , and the point has countable character in , then is Lindelöf; b) if is a cozero subspace of a Tychonoff space , then and .
On the maximal -compactification of products of two -spaces.
On the metrizability of -spaces and its relationship to the normal Moore space conjecture
On the -fold symmetric product of a space with a --property -network (-network)
We study the relation between a space satisfying certain generalized metric properties and its -fold symmetric product satisfying the same properties. We prove that has a --property -network if and only if so does . Moreover, if is regular then has a --property -network if and only if so does . By these results, we obtain that is strict -space (strict -space) if and only if so is .
On the Nachbin compactification of products of totally ordered spaces.
On the Noetherian type of topological spaces
The Noetherian type of topological spaces is introduced. Connections between the Noetherian type and other cardinal functions of topological spaces are obtained.
On the Novák completion of convergence groups
On the open-open game
We modify a game due to Berner and Juhász to get what we call “the open-open game (of length ω)”: a round consists of player I choosing a nonempty open subset of a space X and II choosing a nonempty open subset of I’s choice; I wins if the union of II’s open sets is dense in X, otherwise II wins. This game is of interest for ccc spaces. It can be translated into a game on partial orders (trees and Boolean algebras, for example). We present basic results and various conditions under which I or II...
On the paracompactness of frames
Through the study of frame congruences, new characterizations of the paracompactness of frames are obtained.
On the preservation of separation axioms in products
We give sufficient and necessary conditions to be fulfilled by a filter and an ideal in order that the -quotient space of the -ideal product space preserves -properties () (“in the sense of the Łos theorem”). Tychonoff products, box products and ultraproducts appear as special cases of the general construction.
On the problem of preserving the class of continuous real functions
On the product of a compact space with an hereditarily absolutely countably compact space
We show that the product of a compact, sequential space with an hereditarily absolutely countably compact space is hereditarily absolutely countably compact, and further that the product of a compact space of countable tightness with an hereditarily absolutely countably compact -bounded space is hereditarily absolutely countably compact.
On the product of a perfect paracompact space and a countable product of scattered paracompact spaces