Construct a sequence whose set of limit points is exactly the set of integers?

In summary, to construct a sequence with a set of limit points that is exactly the set of integers, you need to have an infinite number of terms that arrive at each integer. This can be achieved by mapping the natural numbers onto a countable set of numbers that satisfy this criteria. One possible sequence that meets these requirements is: 0, 0, -1, 1, 0, -1, 1, -2, 2, 0, -1, 1, -2, 2, -3, 3,...
  • #1
hb1547
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Homework Statement


"Construct a sequence whose set of limit points is exactly the set of integers?"

The Attempt at a Solution


I need a sequence that will have an infinite number of terms that arrive at each of the integers, right?
And since the sequence is indexed by the natural numbers, doesn't that mean I need some kind of mapping from the natural numbers into the integers that meets that criteria?
 
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  • #2
Yes, you need an (infinite) sequence that arrives at each of the integers (make this precise). I'd imagine you can think of several sets of numbers that satisfy this criteria. If these sets are countable, all that remains is to think of some way to map the naturals onto one of those sets. If you have a set in mind, we may be able to give you more targeted hints.
 
  • #3
My best guess was something like:

0, 0, -1, 1, 0, -1, 1, -2, 2, 0, -1, 1, -2, 2, -3, 3,...

Would that work?
 

Related to Construct a sequence whose set of limit points is exactly the set of integers?

1. How do you construct a sequence with a set of limit points that is exactly the set of integers?

To construct a sequence with a set of limit points that is exactly the set of integers, you can use the formula a_n = n, where n is a positive integer. This will produce a sequence of positive integers that will have all integers as its limit points.

2. Can a sequence have a set of limit points that is exactly the set of integers?

Yes, a sequence can have a set of limit points that is exactly the set of integers. As mentioned in the previous answer, using the formula a_n = n will produce such a sequence.

3. What are the limit points of a sequence with a set of limit points that is exactly the set of integers?

The limit points of a sequence with a set of limit points that is exactly the set of integers are all integers. This means that for any positive integer n, there will be infinitely many terms in the sequence that are within a distance of 1/n from n.

4. Is there a unique way to construct a sequence with a set of limit points that is exactly the set of integers?

Yes, there is a unique way to construct a sequence with a set of limit points that is exactly the set of integers. As mentioned before, using the formula a_n = n will produce such a sequence. However, there may be other ways to construct such a sequence as well.

5. Can a sequence have a finite set of limit points that is exactly the set of integers?

No, a sequence cannot have a finite set of limit points that is exactly the set of integers. The set of integers is infinite, so any sequence with the set of integers as its limit points will also have an infinite number of limit points.

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