Can Every Compact Metric Space Have a Countable Base?

  • Thread starter imahnfire
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In summary, the conversation discusses Rudin's problem which asks to prove that every compact metric space has a countable base. The validity of this statement is questioned and it is clarified that Rudin defines countable as either finite or in bijection with \mathbb{N}. It is suggested to look up his definition to be sure. It is also mentioned that Rudin distinguishes between finite and countable sets, which affects the validity of the statement as the base should be either finite or countable.
  • #1
imahnfire
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0
Rudin's problem asks: Prove that every compact metric space K has a countable base.

My concern is how valid this statement really is. Wouldn't a finite compact metric space be unable to have a countable base?
 
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  • #2
Rudin probably defines countable as either finite or in bijection with [itex]\mathbb{N}[/itex]. So finite things are countable to him.

You should look up his definition to be sure.
 
  • #3
Rudin distinguishes finite sets and countable sets in his book. Would this affect the validity of the statement?
 
  • #4
imahnfire said:
Rudin distinguishes finite sets and countable sets in his book. Would this affect the validity of the statement?

Yes, it does. You want the base to be either finite or countable.
 

1. What is the problem statement in Rudin Chapter 2 Problem 25?

The problem asks to prove the existence of a certain type of sequence in a metric space, given certain conditions.

2. What is a metric space?

A metric space is a set of points with a distance function defined between them.

3. What are the conditions given in the problem?

The conditions state that the metric space must be complete and separable.

4. What is a complete metric space?

A complete metric space is one in which all Cauchy sequences converge to a point within the space.

5. What is a separable metric space?

A separable metric space is one that contains a countable dense subset, meaning there exists a countably infinite set of points that are "close" to every point in the space.

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