Retracts and extension spaces for perfectly normal spaces - II
Rings Of Real-Valued Functions And The Finite Subcovering Property.
r-Realcompact spaces
A new generalization of realcompactness based on ultrafilters of regular -subsets is introduced. Its relationship with realcompactness, almost realcompactness, almost* realcompactness, c-realcompactness is examined. Some of the properties of the newly introduced space is studied as well.
Rudin's Dowker space in the extension with a Suslin tree
We introduce a generalization of a Dowker space constructed from a Suslin tree by Mary Ellen Rudin, and the rectangle refining property for forcing notions, which modifies the one for partitions due to Paul B. Larson and Stevo Todorčević and is stronger than the countable chain condition. It is proved that Martin's Axiom for forcing notions with the rectangle refining property implies that every generalized Rudin space constructed from Aronszajn trees is non-Dowker, and that the same can be forced...
-spaces and -sets
-point finite refinable spaces.
Samuel compactification and uniform coreflection of nearness -frames
We introduce the structure of a nearness on a -frame and construct the coreflection of the category of nearness -frames to the category of compact regular -frames. This description of the Samuel compactification of a nearness -frame is in analogy to the construction by Baboolal and Ori for nearness frames in [1] and that of Walters for uniform -frames in [11]. We also construct the uniform coreflection of a nearness -frame, that is, the coreflection of the category of to the category...
Scattered compactification for the Arens’ space
Scattered compactifications
Seeking a network characterization of Corson compacta
We say that a collection of subsets of has property if there is a set and point-countable collections of closed subsets of such that for any there is a finite subcollection of such that . Then we prove that any compact space is Corson if and only if it has a point-- base. A characterization of Corson compacta in terms of (strong) point network is also given. This provides an answer to an open question in “A Biased View of Topology as a Tool in Functional Analysis” (2014) by...
Selection principles and Baire spaces
Selection principles and upper semicontinuous functions
In connection with a conjecture of Scheepers, Bukovský introduced properties wQN* and SSP* and asked whether wQN* implies SSP*. We prove it in this paper. We also give characterizations of properties S₁(Γ,Ω) and in terms of upper semicontinuous functions
Semi separation axioms and hyperspaces.
Semialgebraic Topology Over a Real Closed Field I: Paths and Components in the Set of Rational Points of an Algebraic Variety.
Semialgebraic Topology over a Real Closed Field II: Basic Theory of Semialgebraic Spaces.
Semicompactness in fuzzy topological spaces.
Semiconvex compacta
We define and investigate a generalization of the notion of convex compacta. Namely, for semiconvex combination in a semiconvex compactum we allow the existence of non-trivial loops connecting a point with itself. It is proved that any semiconvex compactum contains two non-empty convex compacta, the center and the weak center. The center is the largest compactum such that semiconvex combination induces a convex structure on it. The convex structure on the weak center does not necessarily coincide...
Semi-generalized continuous maps in topological spaces.
Semigroup structure in compactifications of ordered semigroups
Semigroupes semitopologiques compacts admettant un sous-groupe dense.