scholarly journals P-Normality

2021 ◽  
Vol 12 (6) ◽  
pp. 1-8
Author(s):  
LUTFI KALANTAN ◽  
MAI MANSOURI
Keyword(s):  
Topological Space ◽  
Normal Space ◽  
Bijective Function

A topological space X is called P-normal if there exist a normal space Y and a bijective function f : X −→ Y such that the restriction f|A : A −→ f(A) is a homeomorphism for each paracompact subspace A ⊆ X. We will investigate this property and produce some examples to illustrate the relation between P-normality and other weaker kinds of normality.

scholarly journals C-normal topological property

Filomat ◽  
2017 ◽  
Vol 31 (2) ◽  
pp. 407-411 ◽  
Author(s):  
Samirah AlZahrani ◽  
Lutfi Kalantan
Keyword(s):  
Topological Space ◽  
Topological Property ◽  
Normal Space ◽  
Compact Subspace ◽  
Bijective Function

A topological space X is called C-normal if there exist a normal space Y and a bijective function f : X ? Y such that the restriction f _ C : C ? f (C) is a homeomorphism for each compact subspace C ? X. We investigate this property and present some examples to illustrate the relationships between C-normality and other weaker kinds of normality.

On Certain Onto Maps

1962 ◽  
Vol 14 ◽  
pp. 461-466 ◽  
Author(s):  
Isaac Namioka
Keyword(s):  
Topological Space ◽  
Closed Subspace ◽  
Dimensional Space ◽  
Extension Theorem ◽  
Normal Space ◽  
Continuous Map ◽  
Image Position

Let Δn (n > 0) denote the subset of the Euclidean (n + 1)-dimensional space defined byA subset σ of Δn is called a face if there exists a sequence 0 ≤ i1 ≤ i2 ≤ … < im ≤ n such thatand the dimension of σ is defined to be (n — m). Let denote the union of all faces of Δn of dimensions less than n. A topological space Y is called solid if any continuous map on a closed subspace A of a normal space X into Y can be extended to a map on X into Y. By Tietz's extension theorem, each face of Δn is solid. The present paper is concerned with a generalization of the following theorem which seems well known.

scholarly journals On normal subspaces

1981 ◽  
Vol 23 (1) ◽  
pp. 1-4
Author(s):  
D.B. Gauld ◽  
I.L. Reilly ◽  
M.K. Vamanamurthy
Keyword(s):  
Topological Space ◽  
Normal Space

In this paper the anti-normal property is studied. A space is anti-normal if its only normal subspaces are those whose cardinalities require them to be normal. It is shown that every topological space of at least four elements contains a normal three point subspace from which it follows that there is only one non-trivial anti-normal space.

scholarly journals LINEARLY ORDERED SPACE WHOSE SQUARE AND HIGHER POWERS CANNOT BE CONDENSED ONTO A NORMAL SPACE

2017 ◽  
Vol 20 (10) ◽  
pp. 68-73
Author(s):  
O.I. Pavlov
Keyword(s):  
Topological Space ◽  
Normal Space ◽  
Topological Properties ◽  
Pseudocompact Spaces ◽  
Countably Compact ◽  
Ordered Space ◽  
One To One ◽  
Hereditary Properties

One of the central tasks in the theory of condensations is to describe topological properties that can be improved by condensation (i.e. a continuous one-to-one mapping). Most of the known counterexamples in the field deal with non-hereditary properties. We construct a countably compact linearly ordered (hence, monotonically normal, thus ” very strongly” hereditarily normal) topological space whose square and higher powers cannot be condensed onto a normal space. The constructed space is necessarily pseudocompact in all the powers, which complements a known result on condensations of non-pseudocompact spaces.

Even Covering Properties and Somewhat Normal Spaces

1986 ◽  
Vol 29 (2) ◽  
pp. 154-159
Author(s):  
Hans-Peter Künzi ◽  
Peter Fletcher
Keyword(s):  
Topological Space ◽  
Open Cover ◽  
Normal Space ◽  
Completely Regular ◽  
Covering Properties ◽  
Normal Cover

AbstractA topological space X is said to be somewhat normal provided that for each open cover is a normal cover of X. We show that a completely regular somewhat normal space need not be normal, thereby answering a question of W. M. Fleischman. We note that a collectionwise normal somewhat normal space need not be almost 2-fully normal, as had previously been asserted, and that neither the perfect image nor the perfect preimage of a somewhat normal space has to be somewhat normal.

scholarly journals S-paracompactness and S2-paracompactness

Filomat ◽  
2019 ◽  
Vol 33 (17) ◽  
pp. 5645-5650
Author(s):  
Ohud Alghamdi ◽  
Lutfi Kalantan ◽  
Wafa Alagal
Keyword(s):  
Topological Space ◽  
Restriction Map ◽  
Paracompact Space ◽  
Separable Subspace ◽  
Bijective Function

A topological space X is an S-paracompact if there exists a bijective function f from X onto a paracompact space Y such that for every separable subspace A of X the restriction map f|A from A onto f (A) is a homeomorphism. Moreover, if Y is Hausdorff, then X is called S2-paracompact. We investigate these two properties.

On Extensions of Topologies

1967 ◽  
Vol 19 ◽  
pp. 474-487 ◽  
Author(s):  
Carlos J. R. Borges
Keyword(s):  
Topological Space ◽  
Closed Subset ◽  
Normal Space ◽  
Regular Space ◽  
Simple Extension ◽  
Completely Regular ◽  
Countably Compact

If (X, τ) is a topological space (with topology τ) and A is a subset of X, then the topology τ(A) = {U ⋃ (V ⋂ A)|U, V ∈ τ} is said to be a simple extension of τ. It seems that N. Levine introduced this concept in (4) and he proved, among other results, the following:(A) If (X, τ) is a regular (completely regular) space and A is a closed subset of X, then (X, τ(A)) is a regular (completely regular) space.(B) Let (X, τ) be a normal space, and A a closed subset of X. Then (X, τ(A)) is normal if and only if X — A is a normal subspace of (X, τ).(C) Let (X, τ) be a countably compact (compact or Lindelöf) and A ∉ τ.

scholarly journals Results on C2-paracompactness

2021 ◽  
Vol 14 (2) ◽  
pp. 351-357
Author(s):  
Hala Alzumi ◽  
Lutfi Kalantan ◽  
Maha Mohammed Saeed
Keyword(s):  
Topological Space ◽  
Paracompact Space ◽  
Compact Subspace ◽  
Bijective Function

A C-paracompact is a topological space X associated with a paracompact space Y and a bijective function f : X −→ Y satisfying that f A: A −→ f(A) is a homeomorphism for each compact subspace A ⊆ X. Furthermore, X is called C2-paracompact if Y is T2 paracompact. In this article, we discuss the above concepts and answer the problem of Arhangel’ski ̆i. Moreover, we prove that the sigma product Σ(0) can not be condensed onto a T2 paracompact space.

scholarly journals A topological lattice on the set of multifunctions

1989 ◽  
Vol 12 (4) ◽  
pp. 665-668
Author(s):  
Basil K. Papadopoulos
Keyword(s):  
Topological Space ◽  
Partial Order ◽  
Normal Space ◽  
Compact Open Topology ◽  
Topological Lattice

Let X be a Wilker space and M(X,Y) the set of continuous multifunctions from X to a topological space Y equipped with the compact-open topology. Assuming that M(X,Y) is equipped with the partial order⊂we prove that(M(X,Y),⊂)is a topological V-semilattice. We also prove that if X is a Wilker normal space and U(X,Y) is the set of point-closed upper semi-continuous multifunctlons equipped with the compact-open topology, then(U(X,Y),⊂)is a topological lattice.

COMBINATORIAL POLYNOMIALLY COMPUTABLE CHARACTERISTICS OF SUBSTITUTIONS AND THEIR PROPERTIES

2020 ◽  
Vol 7 (2) ◽  
pp. 34-41
Author(s):  
VLADIMIR NIKONOV ◽  
◽  
ANTON ZOBOV ◽  
Keyword(s):  
Mathematical Expectation ◽  
Point Of View ◽  
Small Range ◽  
Computational Point ◽  
Wide Range ◽  
Bijective Function ◽  
The Difference ◽  
Element Base ◽  
Selection Of

The construction and selection of a suitable bijective function, that is, substitution, is now becoming an important applied task, particularly for building block encryption systems. Many articles have suggested using different approaches to determining the quality of substitution, but most of them are highly computationally complex. The solution of this problem will significantly expand the range of methods for constructing and analyzing scheme in information protection systems. The purpose of research is to find easily measurable characteristics of substitutions, allowing to evaluate their quality, and also measures of the proximity of a particular substitutions to a random one, or its distance from it. For this purpose, several characteristics were proposed in this work: difference and polynomial, and their mathematical expectation was found, as well as variance for the difference characteristic. This allows us to make a conclusion about its quality by comparing the result of calculating the characteristic for a particular substitution with the calculated mathematical expectation. From a computational point of view, the thesises of the article are of exceptional interest due to the simplicity of the algorithm for quantifying the quality of bijective function substitutions. By its nature, the operation of calculating the difference characteristic carries out a simple summation of integer terms in a fixed and small range. Such an operation, both in the modern and in the prospective element base, is embedded in the logic of a wide range of functional elements, especially when implementing computational actions in the optical range, or on other carriers related to the field of nanotechnology.

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