Results 81 to 90 of about 383 (157)

A Short Study of Alexandroff Spaces

open access: yes, 2007
In this paper, we discuss the basic properties of Alexandroff spaces. Several examples of Alexandroff spaces are given. We show how to construct new Alexandroff spaces from given ones. Finally, two invariants for compact Alexandroff spaces are defined and calculated for the given examples.
openaire   +2 more sources

Orders, Alexandroff spaces and digraphs

open access: yes, 2021
This thesis mainly deals with Alexandroff spaces which are related to some concepts like preorders, graphs and digraphs.The first chapter gives some basic notions about topology, order and minimal open sets, which are used in the next chapter.In the second chapter, Alexandroff spaces are defined by using minimal open sets, and definitions of preorder ...
openaire   +1 more source

$g^\ast $-closed sets and a new separation axiom in Alexandroff spaces

open access: yes, 2003
summary:In this paper we introduce the concept of $g^{\ast }$-closed sets and investigate some of its properties in the spaces considered by A. D. Alexandroff [1] where only countable unions of open sets are required to be open.
Rashid, Md. Mamun Ar, Das, Pratulananda
core  

Transversal and T1-independent topologies and the Alexandroff duplicate

open access: yes, 2012
Two T1-topologies on a given set are called transversal if their union is a subbase for the discrete topology, and T1-independent if their intersection is the cofinite topology.
M. Tkachenko   +3 more
core   +1 more source

Extensions of topological spaces with strongly-discrete remainder

open access: yes, 1999
The construction of the Alexandroff one-point compactification is extended to provide paracompact extensions of locally compact Hausdorff spaces with strongly-discrete ...
Collins, P.J.
core   +1 more source

Closed graph property in Alexandroff spaces

open access: yes
In the following text we show if $X$ is an Alexandroff space, then $f:X\to Y$ has closed graph if and only if it has constant closed value on each connected component of $X$. Moreover, if $X$ an Alexandroff space and $f:X\to Y$ has closed graph, then $f:X\to Y$ is continuous.
Shirazi, Fatemah Ayatollah Zadeh   +1 more
openaire   +2 more sources

On the Construction of Alexandroff Spaces

open access: yes
Alexandroff spaces, characterized by the property that arbitrary intersections of open sets remain open, play a fundamental role in topology and its applications. This article explores different methods for constructing Alexandroff spaces, organized into
MANCERO MOSQUERA, MARCELO ISAAC   +1 more
core  

H-closed spaces and almost realcompact spaces

open access: yes, 2023
It was P. Alexandroff and P. Urysohn who first introduced the class of H-closed spaces. Since then, it has evoked the interest of many topologists. The concept of H-closedness is closely related to that of compactness, and it is for this reason that ...
Halpin, Katherine
core  

Topological View of Flows Inside the BOLD Spontaneous Activity of the Human Brain. [PDF]

open access: yesFront Comput Neurosci, 2020
Don APH, Peters JF, Ramanna S, Tozzi A.
europepmc   +1 more source

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