Let $X$ is a nonempty set with $m$ members . How many $\sigma$ -algebra can we make on this set?
Number of $\sigma$ -Algebra on the finite set
25
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real-analysis
measure-theory
elementary-set-theory
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2I think number of $\sigma$-algebra is less than $2^{n}$ where $n$ is the number of $X$. – 2012-05-11
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0@Alizter I see you opened a bounty because the question has not received enough attention. Do you want my answer to be more detailed? – 2015-04-14
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0@DavideGiraudo I think that would be a good idea. I also think that this question is applicable to a greater audience so perhaps some simpler notation and explanation may be in order. Thank you for responding :) – 2015-04-14