Complete countable metric space

In summary, a complete countable metric space is a countable set of points with a distance function between them that is also complete, meaning that all Cauchy sequences converge to a point within the space. It differs from a general metric space in that it is specifically countable. Completeness is important in a countable metric space because it ensures the accuracy and precision of calculations. A complete countable metric space cannot be uncountable, and examples include the set of rational numbers, integers, and finite subsets of a given set.
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hedipaldi
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Homework Statement



It is clear that a countable complete metric space must have an isolated point,moreover,the set of isolated points is dense.what example is there of a countable complete metric space with points that are not isolated?

Homework Equations





The Attempt at a Solution

 
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  • #2
No need'I found an example.
 

1. What is a complete countable metric space?

A complete countable metric space is a mathematical concept that describes a set of points with a distance function between them. It is countable, meaning that it has a finite or countably infinite number of points, and it is complete, meaning that every Cauchy sequence within the space converges to a point within the space itself.

2. How is a complete countable metric space different from a general metric space?

A complete countable metric space is a special type of metric space that has the additional property of being countable. This means that it has a finite or countably infinite number of points, while a general metric space can have any number of points.

3. What is the importance of completeness in a countable metric space?

The completeness of a countable metric space is important because it ensures that all Cauchy sequences, which are sequences that approach a limit, actually converge to a point within the space. This allows for more precise and accurate calculations and analysis within the space.

4. Can a complete countable metric space be uncountable?

No, a complete countable metric space must be countable by definition. An uncountable metric space would not have the property of being countable and therefore would not be considered a complete countable metric space.

5. What are some examples of complete countable metric spaces?

Some examples of complete countable metric spaces include the set of all rational numbers, the set of all integers, and the set of all finite subsets of a given set. These are all countable and have a defined distance function, making them complete countable metric spaces.

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