Computing lebesgue number for an open covering

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In summary, Munkres' proof for the Lebesgue number lemma provides a way to compute δ using a finite subcollection of an open covering of a compact metric space. However, this may not be the smallest Lebesgue number. There may be another proof that involves evaluating the smallest Lebesgue number, if it exists. There is also a discussion about the largest Lebesgue number and how any positive number smaller than a Lebesgue number for a covering is also a Lebesgue number for that covering.
  • #1
Useful nucleus
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Munkres proof for the Lebesgue number lemma which is
(If X is a compact metric space and A is an open covering then there exists δ>0 such that for each subset of X having diameter less than δ , then there exists an element of the covering A containing it)
gives a way to compute δ using a finite subcollection that covers the compact metric space. However, this is not necessarily the smallest Lebesgue number. I wonder if there is another proof that involves evaluating the smallest Lebesgue number, if the latter exists.
 
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  • #2
Useful nucleus, do you mean the largest Lebesgue number? Any positive number smaller than a Lebesgue number for a covering is also a Lebesgue number for the covering.
 
  • #3
lugita15, you are absolutely right, I meant largest Lebesgue number if exist. I did not have time to refelct on this question again, but will give it a try soon.
 

Related to Computing lebesgue number for an open covering

What is the Lebesgue number for an open covering?

The Lebesgue number for an open covering is a measure of the size of the smallest open set that can cover the entire space. It is an important concept in topology and is used to determine the uniformity of a covering of a space.

Why is computing the Lebesgue number important?

Computing the Lebesgue number is important because it helps us understand the structure and topology of a space. It allows us to determine if a covering is uniformly distributed or if there are any gaps or overlaps in the coverage.

How is the Lebesgue number computed?

The Lebesgue number is computed by finding the minimum distance between any two points in the space that are not covered by the same open set. This distance is then divided by 2 to give the Lebesgue number.

Can the Lebesgue number be computed for any space?

Yes, the Lebesgue number can be computed for any space as long as it is a metric space. It is a general concept and can be applied to different types of spaces, such as Euclidean space or topological spaces.

What is the significance of the Lebesgue number in mathematics?

The Lebesgue number has many applications in mathematics, particularly in topology and analysis. It is used to prove the existence of certain structures, such as partitions of unity, and to establish the uniformity of certain coverings. It also helps in the construction of maps and in the study of limit theorems.

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