Subsequential limit question

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In summary, the problem states that if a bounded sequence has limit points of 0 and 1, then there exist two subsequences that converge to these limit points respectively, and each term in the sequence belongs to exactly one of these subsequences. By using the definition of limit points and the bounded property, we can partition the sequence into two subsequences based on whether the terms are less than or greater than 1/2.
  • #1
playa007
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Homework Statement


Suppose {a_n} is a bounded sequence who's set of all subsequential
limits points is {0,1}. Prove that there exists two subsequences,
such that: one subsequence converges to 1 while the other converges
to 0, and each a_n belongs to exactly one of these subsequences.


Homework Equations





The Attempt at a Solution


Well, it's clear that at the limit points 0 and 1; there is a subsequence that that converges to it. I'm not quite sure about how to prove that each a_n belongs to exactly one of these subsequences or how to apply the bounded property of {a_n} into this question.
 
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  • #2
This will depend slightly on the definition you are using.
Suppose {a_n} is a bounded sequence who's set of all subsequential
limits points is {0,1}
Suppose epps is a positive real number
0 and one are limit points so it is known that
(-eps,eps)U(1-eps,1+eps)
Contains all but a finite number of the a_n
now the sequence can be easily partitioned by
1/2
one subsequence if a_n<=1/2
another if a_n>1/2
 

What is a subsequential limit?

A subsequential limit is a value that a sequence of numbers approaches as it continues to grow, without necessarily reaching that value. It is also known as a limit point or accumulation point.

How is a subsequential limit different from a limit?

A limit is a value that a sequence approaches and eventually reaches, while a subsequential limit is a value that a sequence approaches but may never reach. In other words, a subsequential limit is a limit that exists beyond the sequence itself.

How is a subsequential limit calculated?

A subsequential limit is calculated by finding the values that appear most often in a sequence and taking the limit of those values. It can also be calculated by finding the limit of any convergent subsequence of the original sequence.

What is the significance of subsequential limits in mathematics?

Subsequential limits are important in understanding the behavior of sequences and their convergence. They can also be used to prove the existence of limits and to determine the convergence of a sequence.

Can a sequence have more than one subsequential limit?

Yes, a sequence can have multiple subsequential limits. This occurs when the sequence has multiple values that it approaches but does not reach. These values can be different or the same, and they can also be finite or infinite.

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