How to prove there is no Lebesgue number for open cover (1/n,1)?

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The discussion centers on proving the absence of a Lebesgue number for the open cover {(1/n,1)} of the interval (0,1). Participants highlight that any point x in (0,1) is contained within the open sets Ux = (1/n,1), yet the challenge arises when considering the radius r around x. The key insight is to analyze the subintervals of (0,1) that are not fully contained within the sets of the cover, which leads to the conclusion that no single radius can satisfy the Lebesgue number condition.

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ramasamyg
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I am not sure how to prove there is no Lebesgue number for an open cover {(1/n,1)} of interval (0,1). If I take any element x of (0,1), it is inside any of the open set Ux = (1/n,1) of the open cover. So I am not sure how taking a ball of radius r around x is not contained in any Ux.
 
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This should be easy. Do it the other way round.
Think about the subintervals of (0,1) that are not contained within (1/n,1).
 

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