Example of an Empty Intersection with Converging Nested Sets in Incomplete Space

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The discussion centers on providing an example of an empty intersection of decreasing nested closed subsets in an incomplete space. The user proposes using the space X as the rational numbers, denoted as \(\mathbb{Q}\), and defines the sets \(S_n\) as the intervals \([\pi - 1/n, \pi + 1/n]\). This construction demonstrates that while the sets \(S_n\) converge to the point \(\pi\), their intersection remains empty due to the nature of the rational numbers being incomplete.

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Homework Statement


If {[itex]S_n[/itex]} is a nest of decreasing
non-empty closed subsets of X with [itex]\lim_{n\to\infty}d(S_n)=0[/itex],
give an example of [itex]\cap_{n=1}^{\infty}S_n[/itex] which is empty!




Homework Equations



no

The Attempt at a Solution


i know X cannot be R, further reading i know that X cannot be complete. But i cannot think of an incomplete space and a suitable [itex]S_n[/itex].
 
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Any incomplete space should do. I suggest taking [tex]X=\mathbb{Q}[/tex] and setting [tex]S_n=[\pi-1/n,\pi+1/n][/tex].
 

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