On Star-K-I-Hurewicz Property

2021 ◽  
Vol 78 (1) ◽  
pp. 157-166
Author(s):  
Sumit Singh ◽  
Harsh V. S. Chauhan ◽  
Vikesh Kumar

Abstract A space X is said to have the star-K-I-Hurewicz property (SKIH) [Tyagi, B. K.—Singh, S.—Bhardwaj, M. Ideal analogues of some variants of Hurewicz property, Filomat 33 (2019), no. 9, 2725–2734] if for each sequence (Un : n ∈ ℕ) of open covers of X there is a sequence (Kn : n ∈ ℕ) of compact subsets of X such that for each x ∈ X, {n ∈ ℕ : x ∉ St(Kn, Un )} ∈ I, where I is the proper admissible ideal of ℕ. In this paper, we continue to investigate the relationship between the SKIH property and other related properties and study the topological properties of the SKIH property.

Filomat ◽  
2017 ◽  
Vol 31 (5) ◽  
pp. 1279-1285 ◽  
Author(s):  
Yan-Kui Song

A space X is star-K-Hurewicz if for each sequence (Un : n ? N) of open covers of X there exists a sequence (Kn : n ? N) of compact subsets of X such that for each x ? X, x ? St(Kn,Un) for all but finitely many n. In this paper, we investigate the relationship between star-K-Hurewicz spaces and related spaces by giving some examples, and also study topological properties of star-K-Hurewicz spaces.


2020 ◽  
Vol 76 (1) ◽  
pp. 81-94
Author(s):  
Sumit Singh ◽  
Brij K. Tyagi ◽  
Manoj Bhardwaj

AbstractAspace X is said to have the absolutely strongly star -𝒤-Hurewicz (ASS𝒤H) property if for each sequence (𝒰n : n ∈ 𝕅)of opencovers of X and each dense subset Y of X, there is a sequence (Fn : n ∈ 𝕅) of finite subsets of Y such that for each x ∈ X, {n ∈ 𝕅 : x ∉ St(Fn, 𝒰n)}∈ 𝒤, where 𝒤 is the proper admissible ideal of 𝕅. In this paper, we investigate the relationship between the ASS𝒤H property and other related properties and study the topological properties of the ASS𝒤H property. This paper generalizes several results of Song [25] to the larger class of spaces having the ASS𝒤H properties.


Filomat ◽  
2013 ◽  
Vol 27 (5) ◽  
pp. 875-880
Author(s):  
Yan-Kui Song

A space X is said to be neighborhood star-Lindel?f if for every open cover U of X there exists a countable subset A of X such that for every open O?A, X=St(O,U). In this paper, we continue to investigate the relationship between neighborhood star-Lindel?f spaces and related spaces, and study topological properties of neighborhood star-Lindel?f spaces in the classes of normal and pseudocompact spaces. .


2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Ljubiša D. R. Kočinac ◽  
Sumit Singh

A space X is said to be set selectively star-ccc if for each nonempty subset B of X , for each collection U of open sets in X such that B ¯ ⊂ ∪ U , and for each sequence A n : n ∈ ℕ of maximal cellular open families in X , there is a sequence A n : n ∈ ℕ such that, for each n ∈ ℕ , A n ∈ A n and B ⊂ St ∪ n ∈ ℕ A n , U . In this paper, we introduce set selectively star-ccc spaces and investigate the relationship between set selectively star-ccc and other related spaces. We also study the topological properties of set selectively star-ccc spaces. Some open problems are posed.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Ricardo Gabriel Elías ◽  
Nicolás Vidal-Silva ◽  
Vagson L. Carvalho-Santos

Abstract We study the relationship between the winding number of magnetic merons and the Gaussian curvature of two-dimensional magnetic surfaces. We show that positive (negative) Gaussian curvatures privilege merons with positive (negative) winding number. As in the case of unidimensional domain walls, we found that chirality is connected to the polarity of the core. Both effects allow to predict the topological properties of metastable states knowing the geometry of the surface. These features are related with the recently predicted Dzyaloshinskii-Moriya emergent term of curved surfaces. The presented results are at our knowledge the first ones drawing attention about a direct relation between geometric properties of the surfaces and the topology of the hosted solitons.


2010 ◽  
Vol 20 (2) ◽  
pp. 107-126 ◽  
Author(s):  
ULRICH BERGER ◽  
JENS BLANCK ◽  
PETTER KRISTIAN KØBER

We present a method for constructing from a given domain representation of a space X with underlying domain D, a domain representation of a subspace of compact subsets of X where the underlying domain is the Plotkin powerdomain of D. We show that this operation is functorial over a category of domain representations with a natural choice of morphisms. We study the topological properties of the space of representable compact sets and isolate conditions under which all compact subsets of X are representable. Special attention is paid to admissible representations and representations of metric spaces.


2017 ◽  
Author(s):  
Takuya Yabu

In the previous paper, I defined algorithmic manifolds simulating polynomial-time algorithms, and I showed topological properties for P problem and NP problem and that NP problem can be transformed into deterministic Turing machine problem. In this paper, I define algorithmic manifolds simulating exponential-time algorithms and, I show topological properties for EXPTIME problem and NEXPTIME problem. I also discuss the relationship between NEXPTIME and deterministic Turing machines.


CrystEngComm ◽  
2015 ◽  
Vol 17 (23) ◽  
pp. 4325-4333 ◽  
Author(s):  
Clarissa P. Frizzo ◽  
Aniele Z. Tier ◽  
Izabelle M. Gindri ◽  
Alexandre R. Meyer ◽  
Gabrielle Black ◽  
...  

The relationship between energetic and topological properties of crystals with weak electrostatic intermolecular interactions and thermodynamic data are presented.


2017 ◽  
Author(s):  
Takuya Yabu

In the previous paper, algorithmic manifolds were applied to the time complexity and discussed. In this paper, I define algorithmic manifolds expressing space complexity and discuss topological properties. I also discuss the relationship between non-deterministic space complexity problems and deterministic Turing machines.


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