I'm trying to prove the following and all I've got is like one line worth of proof.(adsbygoogle = window.adsbygoogle || []).push({});

If we had that sigma-rings were closed under complementation, this would be easier, but we only know that if A in R and B in R, then A \ B in R and B \ A in R (symmetric difference). Is there a way to approach this using the symmetric difference?

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# Homework Help: Sigma-rings are closed under countable intersections (sigma-rings are delta-rings)

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