Local properties of topological spaces and remainders in compactifications

2019 ◽  
Vol 158 (2) ◽  
pp. 306-317
Author(s):  
A. V. Arhangel’skii
1954 ◽  
Vol 21 (1) ◽  
pp. 163-171 ◽  
Author(s):  
Ernest Michael

Filomat ◽  
2015 ◽  
Vol 29 (1) ◽  
pp. 83-88
Author(s):  
A.V. Arhangel’skii ◽  
S. Tokgöz

Many important examples of topological spaces can be represented as a union of a finite or countable collection of metrizable subspaces. However, it is far from clear which spaces in general can be obtained in this way. Especially interesting is the case when the subspaces are dense in the union. We present below several results in this direction. In particular, we show that if a Tychonoff space X is the union of a countable family of dense metrizable locally compact subspaces, then X itself is metrizable and locally compact. We also prove a similar result for metrizable locally separable spaces. Notice in this connection that the union of two dense metrizable subspaces needn?t be metrizable. Indeed, this is witnessed by a well-known space constructed by R.W. Heath.


2007 ◽  
Vol 44 (02) ◽  
pp. 393-408 ◽  
Author(s):  
Allan Sly

Multifractional Brownian motion is a Gaussian process which has changing scaling properties generated by varying the local Hölder exponent. We show that multifractional Brownian motion is very sensitive to changes in the selected Hölder exponent and has extreme changes in magnitude. We suggest an alternative stochastic process, called integrated fractional white noise, which retains the important local properties but avoids the undesirable oscillations in magnitude. We also show how the Hölder exponent can be estimated locally from discrete data in this model.


1982 ◽  
Vol 43 (6) ◽  
pp. 961-971 ◽  
Author(s):  
J.A. Hodges ◽  
G. Jéhanno ◽  
D. Debray ◽  
F. Holtzberg ◽  
M. Loewenhaupt
Keyword(s):  
X Ray ◽  

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