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Difference between revisions of "Subbase"

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A family <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/p/p074/p074270/p0742701.png" /> of open subsets of a [[Topological space|topological space]] <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/p/p074/p074270/p0742702.png" /> such that the totality of all sets which are intersections of a finite number of elements of <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/p/p074/p074270/p0742703.png" /> forms a [[Base|base]] of <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/p/p074/p074270/p0742704.png" />.
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{{TEX|done}}{{MSC|54A05}}
  
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''pre-base''
  
 
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A family $\gamma$ of open subsets of a [[topological space]] $X$ such that the totality of all sets which are intersections of a finite number of elements of $\gamma$ forms a [[base]] of $X$.
====Comments====
 
The Western term is subbase.
 
  
 
====References====
 
====References====
<table><TR><TD valign="top">[a1]</TD> <TD valign="top">  R. Engelking,  "General topology" , Heldermann  (1989)</TD></TR></table>
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<table>
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<TR><TD valign="top">[a1]</TD> <TD valign="top">  R. Engelking,  "General topology" , Heldermann  (1989)</TD></TR>
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</table>

Latest revision as of 19:22, 19 October 2016

2020 Mathematics Subject Classification: Primary: 54A05 [MSN][ZBL]

pre-base

A family $\gamma$ of open subsets of a topological space $X$ such that the totality of all sets which are intersections of a finite number of elements of $\gamma$ forms a base of $X$.

References

[a1] R. Engelking, "General topology" , Heldermann (1989)
How to Cite This Entry:
Subbase. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Subbase&oldid=16203
This article was adapted from an original article by M.I. Voitsekhovskii (originator), which appeared in Encyclopedia of Mathematics - ISBN 1402006098. See original article