Maximal linked systems and ultrafilters: main representations and topological properties

2020 ◽  
pp. 68-84
Author(s):  
Aleksandr G. Chentsov
Keyword(s):  
Measurable Space ◽  
Topological Properties ◽  
Bitopological Space ◽  
Measurable Structure ◽  
Bitopological Spaces ◽  
Algebras Of Sets

Questions connected with representation of the ultrafilter (UF) set for widely understood measurable space are investigated; this set is considered as a subspace of bitopological space of maximal linked systems (MLS) under equipment with topologies of Wallman and Stone types (measurable structure is defined as a π -system with “zero” and “unit”). Analogous representations connected with generalized variant of cohesion is considered also; in this variant, for corresponding set family, it is postulated the nonemptyness of intersection for finite subfamilies with power not exceeding given. Conditions of identification of UF and MLS (in the above-mentioned generalized sense) are investigated. Constructions reducing to bitopological spaces with points in the form of MLS and 𝑛-supercompactness property generalizing the “usual” supercompactness are considered. Finally, some characteristic properties of MLS and their corollaries connected with the MLS contraction to a smaller π -system are being studied. The case of algebras of sets is selected separately.

MAXIMAL LINKED SYSTEMS AND ULTRAFILTERS OF WIDELY UNDERSTOOD MEASURABLE SPACES

2018 ◽  
pp. 846-860
Author(s):  
Aleksandr Georgievich Chentsov
Keyword(s):  
Sufficient Conditions ◽  
Measurable Space ◽  
Necessary And Sufficient Conditions ◽  
Bitopological Space ◽  
Necessary And Sufficient ◽  
Bitopological Spaces

Two types of set families (ultrafilters or maximal filters and maximal linked systems) for widely understood measurable space are considered. The resulting sets of ultrafilters and maximal linked systems are equipped with the pair of comparable topologies (within the meaning of «Wallman» and «Stone»). As a result, two bitopological spaces are realized; one of them turns out a subspace of another. More precisely, ultrafilters are maximal linked systems and the totality of the latter forms a cumulative bitopological space. With employment of topological constructions some characteristic properties of ultrafilters and (in smaller power) maximal linked systems are obtained (the question is necessary and sufficient conditions of maximality of filters and linked systems).

scholarly journals Some topological properties of the space of maximal linked systems with topology of Wallman type

2020 ◽  
Vol 56 ◽  
pp. 122-137
Author(s):  
A.G. Chentsov
Keyword(s):  
Measurable Space ◽  
Topological Properties ◽  
Bitopological Spaces ◽  
Space Conditions ◽  
Degenerate Cases

Maximal linked systems (MLS) and ultrafilters (u/f) on a widely understood measurable space (this is a nonempty set with equipment in the form of π-system with “zero” and “unit”) are investigated. Under equipment with topology of Wallman type, the set of MLS is converted into a supercompact T1-space. Conditions under which given space of MLS is a supercompactum (i.e., a supercompact T2-space) are investigated. These conditions then apply to the space of u/f under equipment with topology of Wallman type. The obtained conditions are coordinated with representations obtained under degenerate cases of bitopological spaces with topologies of Wallman and Stone types, but they are not the last to be exhausted.

scholarly journals On certain analogues of linkedness and supercompactness

2020 ◽  
Vol 55 ◽  
pp. 113-134
Author(s):  
A.G. Chentsov
Keyword(s):  
Topological Space ◽  
The Family ◽  
Measurable Structure ◽  
Bitopological Spaces ◽  
Algebra Of Sets

Natural generalizations of properties of the family linkedness and the topological space supercompactness are considered. We keep in mind reinforced linkedness when nonemptyness of intersection of preassigned number of sets from a family is postulated. Analogously, supercompactness is modified: it is postulated the existence of an open subbasis for which, from every covering (by sets of the subbasis), it is possible to extract a subcovering with a given number of sets (more precisely, not more than a given number). It is clear that among all families having the reinforced linkedness, one can distinguish families that are maximal in ordering by inclusion. Under natural and (essentially) “minimal”' conditions imposed on the original measurable structure, among the mentioned maximal families with reinforced linkedness, ultrafilters are certainly contained. These ultrafilters form subspaces in the sense of natural topologies corresponding conceptually to schemes of Wallman and Stone. In addition, maximal families with reinforced linkedness, when applying topology of the Wallman type, have the above-mentioned property generalizing supercompactness. Thus, an analogue of the superextension of the $T_1$-space is realized. The comparability of “Wallman”' and “Stone”' topologies is established. As a result, bitopological spaces (BTS) are realized; for these BTS, under equipping with analogous topologies, ultrafilter sets are subspaces. It is indicated that some cases exist when the above-mentioned BTS is nondegenerate in the sense of the distinction for forming topologies. At that time, in the case of “usual” linkedness (this is a particular case of reinforced linkedness), very general classes of spaces are known for which the mentioned BTS are degenerate (the cases when origial set, i.e., “unit”' is equipped with an algebra of sets or a topology).

Introduction to Neutrosophic Soft Bitopological Spaces

2021 ◽  
Author(s):  
Hasan Dadas ◽  
◽  
Sibel Demiralp ◽  
Keyword(s):  
Bitopological Space ◽  
Closed Set ◽  
Soft Topology ◽  
The Subject ◽  
Bitopological Spaces

In this study, the concept of neutrosophic soft bitopological space is defined and it is one of the few studies that have dealt with this concept. In addition, pairwise neutrosophic soft open (closed) set on neutrosophic soft bitopological spaces are studied. Supra neutrosophic soft topology is defined by pairwise neutrosophic soft open sets. Important theorems related to the subject supported with many examples for a better understanding of the subject are given.

scholarly journals Characterizations of Quasi-Metrizable Bitopological Spaces

1988 ◽  
Vol 44 (2) ◽  
pp. 271-274 ◽  
Author(s):  
T. G. Raghavan ◽  
I. L. Reilly
Keyword(s):  
Bitopological Space ◽  
Bitopological Spaces

AbstractIn this paper we prove that a pairwise Hausdorff bitopological space is quasi-metrizable if and only if for each point x ∈ X and for i, j = 1,2, i ≠ j, one can assign nbd bases { S(n, i; x) | n = 1, 2,… } such that (i) y ∉ S (n − 1, i; x) imples S(n, i; x) ∩ S (n, j; y) = φ, (ii) y ∈ S (n, i; x) implies S (n, i; y) ⊂ S(n − 1, i; x). We derive two further results from this.

On pairwise \(\mathcal{N}\)-\(\beta\)-open sets in bitopological spaces

2016 ◽  
Vol 7 (3) ◽  
pp. 152
Author(s):  
Fahad Alsharari ◽  
Abdo Qahis
Keyword(s):  
Continuous Function ◽  
Open Cover ◽  
Bitopological Space ◽  
Open Set ◽  
Bitopological Spaces

In this paper, we introduce the notion of an \((i,j)\)-\(\mathcal{N}\)-\(\beta\)-open set which is a generalization of an \((i,j)\)-\(\beta\)-open set in a bitopological space. Also, we investigate some of its properties and characterizations. Besides, we prove that a pairwise \((i, j)\)-\(\mathcal{N}\)-\(\beta\)-open cover that has a finite (countable) subcover is equivalent to a pairwise \(\beta\)-compact (\(\beta\)-Lindel\"{ö}f) space. Finally, we introduce an \((i, j)\)-\(\mathcal{N}\)-\(\beta\)-continuous function and an \((i, j)\)-\(\mathcal{N}\)-\(\beta\)-irresolute function and obtain some of their properties.

scholarly journals Projective bitopological spaces

1972 ◽  
Vol 13 (3) ◽  
pp. 327-334 ◽  
Author(s):  
M. C. Datta
Keyword(s):  
Projective Spaces ◽  
Topological Spaces ◽  
Bitopological Space ◽  
Extremally Disconnected ◽  
Bitopological Spaces

J. C. Kelly [2] introduced the concept of a bitopological space. Lane [3], Patty [4] and Pervin [5] have continued his work. Our purpose in this paper is to identify the projective objects in a suitable category of bitopological spaces after the manner of Gleason [1] and generalize his theorem that in the category of compact Hausdoriff topological spaces, the projective spaces are precisely the extremally disconnected ones.

scholarly journals Classifications of Pairwise Fuzzy Volterra Spaces

2019 ◽  
Vol 9 (1S5) ◽  
pp. 199-202
Keyword(s):  
The Other ◽  
Bitopological Space ◽  
Dense Sets ◽  
Definition Of ◽  
Residual Sets ◽  
Bitopological Spaces

The main focus of this paper is to introduce the new types of pairwise fuzzy Volterra spaces such as by introducing pairwise fuzzy residual sets in the place of pairwise fuzzy Gδ -sets in the definition of pairwise fuzzy Volterra space, a new kind of fuzzy bitopological space namely, pairwise fuzzy εr -Volterra spaces has been introduced and studied and also by introducing pairwise fuzzy pre-open sets in the place of pairwise fuzzy dense sets in the definition of pairwise fuzzy Volterra space, another kind of fuzzy bitopological space namely, pairwise fuzzy εr - Volterra spaces has been introduced and studied. Some of their characterizations and relationships with the other fuzzy bitopological spaces have been investigated and studied.

scholarly journals Some Results of τ1τ2-δ Semiconnectedness and Compactness in Bitopological Spaces

2018 ◽  
Vol 2018 ◽  
pp. 1-4
Author(s):  
M. Arunmaran ◽  
K. Kannan
Keyword(s):  
Topological Spaces ◽  
Bitopological Space ◽  
Bitopological Spaces ◽  
The Relationship

We are going to establish some results of τ1τ2-δ semiconnectedness and compactness in a bitopological space. Besides, we will investigate several results in τ1τ2-δ semiconnectedness for subsets in bitopological spaces. In particular, we will discuss the relationship related to semiconnectedness between the topological spaces and bitopological space. That is, if a bitopological space (X,τ1,τ2) is τ1τ2-δ semiconnected, then the topological spaces (X,τ1) and (X,τ2) are δ-semiconnected. In addition, we introduce the result which states that a bitopological space (X,τ1,τ2) is τ1τ2-δ semiconnected if and only if X and ϕ are the only subsets of X which are τ1τ2-δ semiclopen sets. Moreover, we have proved some results in compactness also. Altogether, several results of τ1τ2-δ semiconnectedness and compactness in a bitopological space have been discussed.

scholarly journals On T1 T2-g-Open Sets in Bitopological Spaces

2019 ◽  
pp. 1-8
Author(s):  
K. Vithyasangaran ◽  
P. Elango ◽  
S. Sathaananthan ◽  
J. Sriranganesan ◽  
P. Paramadevan
Keyword(s):  
Continuous Function ◽  
Topological Spaces ◽  
Bitopological Space ◽  
Open Set ◽  
Bitopological Spaces

In this paper, we introduced and studied a new kind of generalized open set called τ1τ2-g-open set in a bitopological space (X, τ1, τ2). The properties of this τ1τ2-g-open set are studied and compared with some of the corresponding generalized open sets in general topological spaces and bitopological spaces. We also dened the τ1τ2-g-continuous function and studied some its properties.

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