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Difference between revisions of "G-delta"

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m (moved Set of type F sigma(G delta) to G-delta: Easier to find.)
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''<img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/s/s084/s084740/s0847404.png" />-set (<img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/s/s084/s084740/s0847406.png" />-set)''
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{{MSC|28A33}}
  
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A union (intersection) of a countable number of closed (open) sets. See [[Borel set|Borel set]].
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[[Category:Classical measure theory]]
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{{TEX|done}}
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In a topological space $X$ a subset which is the countable intersection of open sets and which is not itself
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open. See [[Borel set]].

Revision as of 08:30, 16 August 2012

2020 Mathematics Subject Classification: Primary: 28A33 [MSN][ZBL]

In a topological space $X$ a subset which is the countable intersection of open sets and which is not itself open. See Borel set.

How to Cite This Entry:
G-delta. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=G-delta&oldid=27592
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