scholarly journals Characterizations of sn-metrizable spaces

2003 ◽  
Vol 74 (88) ◽  
pp. 121-128 ◽  
Author(s):  
Ying Ge
Keyword(s):  
Metric Space ◽  
Metrizable Space ◽  
Finite Point ◽  
Locally Finite ◽  
Metrizable Spaces

We give some characterizations of sn-metrizable spaces. We prove that a space is an sn-metrizable space if and only if it has a locally-finite point-star sn-network. As an application of the result, a space is an sn-metrizable space if and only if it is a sequentially quotient, ? (compact), ?-image of a metric space.

scholarly journals so-metrizable spaces and images of metric spaces

2021 ◽  
Vol 19 (1) ◽  
pp. 1145-1152
Author(s):  
Songlin Yang ◽  
Xun Ge
Keyword(s):  
Metric Space ◽  
Metric Spaces ◽  
Metrizable Space ◽  
Open Mapping ◽  
Generalized Metric Space ◽  
Locally Finite ◽  
Generalized Metric Spaces ◽  
Covering Mapping ◽  
Generalized Metric ◽  
Metrizable Spaces

Abstract so-metrizable spaces are a class of important generalized metric spaces between metric spaces and s n sn -metrizable spaces where a space is called an so-metrizable space if it has a σ \sigma -locally finite so-network. As the further work that attaches to the celebrated Alexandrov conjecture, it is interesting to characterize so-metrizable spaces by images of metric spaces. This paper gives such characterizations for so-metrizable spaces. More precisely, this paper introduces so-open mappings and uses the “Pomomarev’s method” to prove that a space X X is an so-metrizable space if and only if it is an so-open, compact-covering, σ \sigma -image of a metric space, if and only if it is an so-open, σ \sigma -image of a metric space. In addition, it is shown that so-open mapping is a simplified form of s n sn -open mapping (resp. 2-sequence-covering mapping if the domain is metrizable). Results of this paper give some new characterizations of so-metrizable spaces and establish some equivalent relations among so-open mapping, s n sn -open mapping and 2-sequence-covering mapping, which further enrich and deepen generalized metric space theory.

scholarly journals Monad Metrizable Space

Mathematics ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1891
Author(s):  
Orhan Göçür
Keyword(s):  
Metric Space ◽  
Metric Spaces ◽  
Real Space ◽  
Metrizable Space ◽  
Topological Spaces ◽  
Metrizable Spaces

Do the topologies of each dimension have to be same and metrizable for metricization of any space? I show that this is not necessary with monad metrizable spaces. For example, a monad metrizable space may have got any indiscrete topologies, discrete topologies, different metric spaces, or any topological spaces in each different dimension. I compute the distance in real space between such topologies. First, the passing points between different topologies is defined and then a monad metric is defined. Then I provide definitions and some properties about monad metrizable spaces and PAS metric spaces. I show that any PAS metric space is also a monad metrizable space. Moreover, some properties and some examples about them are presented.

scholarly journals τ-metrizable spaces

2018 ◽  
Vol 19 (2) ◽  
pp. 253
Author(s):  
A.C. Megaritis
Keyword(s):  
Metric Space ◽  
Metric Spaces ◽  
Cardinal Number ◽  
Metrizable Space ◽  
Cardinal Numbers ◽  
Metrizable Spaces

<p>In [1], A. A. Borubaev introduced the concept of τ-metric space, where τ is an arbitrary cardinal number. The class of τ-metric spaces as τ runs through the cardinal numbers contains all ordinary metric spaces (for τ = 1) and thus these spaces are a generalization of metric spaces. In this paper the notion of τ-metrizable space is considered.</p>

scholarly journals Preservations of so-metrizable spaces

Filomat ◽  
2012 ◽  
Vol 26 (4) ◽  
pp. 801-807 ◽  
Author(s):  
Shou Lin ◽  
Ying Ge
Keyword(s):  
Topological Group ◽  
Affirmative Answer ◽  
Metrizable Space ◽  
Regular Space ◽  
Locally Finite ◽  
Open Network ◽  
Covering Mappings ◽  
Metrizable Spaces ◽  
Closed Mappings ◽  
Closed Image

A space is called an so-metrizable space if it is a regular space with a ?-locally finite sequentially open network. This paper proves that so-metrizable spaces are preserved under perfect mappings and under closed sequence-covering mappings, which give an affirmative answer to a question on preservations of so-metrizable spaces under some closed mappings. Also, we prove that the closed image of an so-metrizable space is an so-metrizable space if it is a topological group.

scholarly journals Peano compactifications and propertySmetric spaces

1980 ◽  
Vol 3 (4) ◽  
pp. 695-700
Author(s):  
R. F. Dickman
Keyword(s):  
Metric Space ◽  
Metric Spaces ◽  
Metrizable Space ◽  
Connected Sets ◽  
Metrizable Spaces ◽  
Necessary And Sufficient ◽  
Separable Metric Space

Let(X,d)denote a locally connected, connected separable metric space. We say theXisS-metrizable provided there is a topologically equivalent metricρonXsuch that(X,ρ)has PropertyS, i.e. for anyϵ>0,Xis the union of finitely many connected sets ofρ-diameter less thanϵ. It is well-known thatS-metrizable spaces are locally connected and that ifρis a PropertySmetric forX, then the usual metric completion(X˜,ρ˜)of(X,ρ)is a compact, locally connected, connected metric space, i.e.(X˜,ρ˜)is a Peano compactification of(X,ρ). There are easily constructed examples of locally connected connected metric spaces which fail to beS-metrizable, however the author does not know of a non-S-metrizable space(X,d)which has a Peano compactification. In this paper we conjecture that: If(P,ρ)a Peano compactification of(X,ρ|X),Xmust beS-metrizable. Several (new) necessary and sufficient for a space to beS-metrizable are given, together with an example of non-S-metrizable space which fails to have a Peano compactification.

scholarly journals Regular bases at non-isolated points and metrization theorems

2012 ◽  
Vol 49 (1) ◽  
pp. 91-105 ◽  
Author(s):  
Fucai Lin ◽  
Shou Lin ◽  
Heikki Junnila
Keyword(s):  
Affirmative Answer ◽  
Metrizable Space ◽  
Regular Space ◽  
Countable Base ◽  
Locally Finite ◽  
Finite Base ◽  
Isolated Points ◽  
Metrizable Spaces ◽  
Perfect Space

In this paper, we define the spaces with a regular base at non-isolated points and discuss some metrization theorems. We firstly show that a space X is a metrizable space, if and only if X is a regular space with a σ-locally finite base at non-isolated points, if and only if X is a perfect space with a regular base at non-isolated points, if and only if X is a β-space with a regular base at non-isolated points. In addition, we also discuss the relations between the spaces with a regular base at non-isolated points and some generalized metrizable spaces. Finally, we give an affirmative answer for a question posed by F. C. Lin and S. Lin in [7], which also shows that a space with a regular base at non-isolated points has a point-countable base.

Remetrization in Strongly Countabledimensional Spaces

1969 ◽  
Vol 21 ◽  
pp. 748-750 ◽  
Author(s):  
B. R. Wenner
Keyword(s):  
Metric Space ◽  
Metrizable Space ◽  
Dimension Function ◽  
Image Position ◽  
Necessary And Sufficient

Although the Lebesgue dimension function is topologically invariant, the dimension-theoretic properties of a metric space can sometimes be made clearer by the introduction of a new, topologically equivalent metric. A considerable amount of effort has been devoted to the problem of constructing such metrics; one example of the fruits of this research is the following theorem by Nagata (2, Theorem 5).In order that dim R ≦ n for a metrizable space R it is necessary and sufficient to be able to define a metric p(x, y) agreeing with the topology of R such that for every ∊ > 0 and for every point x oƒ R,implyA metric ρ which satisfies the condition of this theorem is called Nagata's metric (this term was introduced, to the best of the author's knowledge, by Nagami (1, Definition 9.3)).

More on Extending Continuous Pseudometrics

1970 ◽  
Vol 22 (5) ◽  
pp. 984-993 ◽  
Author(s):  
H. L. Shapiro
Keyword(s):  
Topological Space ◽  
Metric Space ◽  
Closed Subset ◽  
Locally Finite ◽  
Whole Space

The concept of extending to a topological space X a continuous pseudometric defined on a subspace S of X has been shown to be very useful. This problem was first studied by Hausdorff for the metric case in 1930 [9]. Hausdorff showed that a continuous metric on a closed subset of a metric space can be extended to a continuous metric on the whole space. Bing [4] and Arens [3] rediscovered this result independently. Recently, Shapiro [15] and Alo and Shapiro [1] studied various embeddings. It has been shown that extending pseudometrics can be characterized in terms of extending refinements of various types of open covers. In this paper we continue our study of extending pseudometrics. First we show that extending pseudometrics can be characterized in terms of σ-locally finite and σ-discrete covers. We then investigate when can certain types of covers be extended.

scholarly journals Bombay hypertopologies

2003 ◽  
Vol 4 (2) ◽  
pp. 421 ◽  
Author(s):  
Giuseppe Di Maio ◽  
Enrico Meccariello ◽  
Somashekhar Naimpally
Keyword(s):  
Topological Space ◽  
Metric Space ◽  
Wijsman Convergence ◽  
Locally Finite ◽  
Simple Result ◽  
Special Cases ◽  
Wijsman Topology

<p>Recently it was shown that, in a metric space, the upper Wijsman convergence can be topologized with the introduction of a new far-miss topology. The resulting Wijsman topology is a mixture of the ball topology and the proximal ball topology. It leads easily to the generalized or g-Wijsman topology on the hyperspace of any topological space with a compatible LO-proximity and a cobase (i.e. a family of closed subsets which is closed under finite unions and which contains all singletons). Further generalization involving a topological space with two compatible LO-proximities and a cobase results in a new hypertopology which we call the Bombay topology. The generalized locally finite Bombay topology includes the known hypertopologies as special cases and moreover it gives birth to many new hypertopologies. We show how it facilitates comparison of any two hypertopologies by proving one simple result of which most of the existing results are easy consequences.</p>

Point Sets and Dynamical Systems In the Autocorrelation Topology

2004 ◽  
Vol 47 (1) ◽  
pp. 82-99 ◽  
Author(s):  
Robert V. Moody ◽  
Nicolae Strungaru
Keyword(s):  
Dynamical System ◽  
Point Sets ◽  
Finite Point ◽  
Locally Finite ◽  
Uniform Topology ◽  
Regular Model ◽  
Model Sets ◽  
Project Scheme ◽  
Compact Abelian Groups ◽  
Delone Sets

AbstractThis paper is about the topologies arising from statistical coincidence on locally finite point sets in locally compact Abelian groupsG. The first part defines a uniform topology (autocorrelation topology) and proves that, in effect, the set of all locally finite subsets ofGis complete in this topology. Notions of statistical relative denseness, statistical uniform discreteness, and statistical Delone sets are introduced.The second part looks at the consequences of mixing the original and autocorrelation topologies, which together produce a new Abelian group, the autocorrelation group. In particular the relation between its compactness (which leads then to aG-dynamical system) and pure point diffractivity is considered. Finally for generic regular model sets it is shown that the autocorrelation group can be identified with the associated compact group of the cut and project scheme that defines it. For such a set the autocorrelation group, as aG-dynamical system, is a factor of the dynamical local hull.

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