Difference between revisions of "G-delta"

Latest revision as of 18:22, 18 August 2012

2020 Mathematics Subject Classification: Primary: 28A05 [MSN][ZBL]

In a topological space $X$ a subset which is the countable intersection of open sets. See Borel set and also F-sigma.

How to Cite This Entry:
G-delta. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=G-delta&oldid=12499

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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)''
+{{MSC|28A05}}
-A union (intersection) of a countable number of closed (open) sets. See [[Borel set|Borel set]].
+[[Category:Classical measure theory]]
+{{TEX|done}}
+In a topological space $X$ a subset which is the countable intersection of open sets. See [[Borel set]] and also [[F-sigma]].