Exploring the Cardinality of Cantor Set and Real Numbers

In summary, the conversation discusses the problem and partial solution attached in a PDF file. The person is seeking feedback on the proof and ideas for generalizing or extending it to prove the second statement. The discussion also touches on the use of a ternary expansion correspondence between the Cantor set and the reals, and the issue of waiting for approval when posting images. The conversation also mentions Theorem 2.20 (e) which states the existence of a real number that relates to the linear transformation of a Lebesgue measurable set. Finally, there is a question about how to determine the Lebesgue measure of the Cantor set.
  • #1
benorin
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So the problem, and my partial solution are in the attached PDF.

I would like feedback on my proof of the first statement, if it is technically correct and if it is good. Any ideas as to how I can use/generalize/extend the present proof to proof the second statement, namely that E (the Cantor set) has the same cardinality as [tex]\mathbb{R}[/tex]? Please, not the ternary expansion correspondence to the reals in [0,1]:biggrin: .
 

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  • Show that Cantor set is measure zero.pdf
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  • #2
You might consider summarizing your arguments here since your attachment isn't visible until it gets approved.

From the words you use it sounds like you are using the standard argument that the Cantor set consists of all ternary numbers expanded as decimals that do not contain the digit "1" Obviously, that set has the same cardinality as the reals using Cantor's diagonalization.
 
  • #3
If I post it as a JPEG or BMP or other graphics file, will I still have to wait for this pending approval stuff?

Wrong dimensions! Hate image crap, what with the "waiting for approval" stuff ? Manual content approval or what?
 
Last edited:
  • #4
OK, so its no longer pending approval (and I have gotten some sleep). Please respond soon, this is due in the morning.

Thanks,
-Ben
 
Last edited:
  • #5
FYI, Theorem 2.20 (e) states that to every linear transformation [tex]T:\mathbb{R}^{k}\rightarrow\mathbb{R}^{k}[/tex] there exists a real number [tex]\Delta \left( T\right)[/tex] such that [tex]m\left( T\left( A\right) \right) = \Delta \left( T\right) m\left( A\right) [/tex] for every Lebesgue measurable set A.
 
  • #6
How do you know that the Cantor set actually has a Lebesgue measure? Beyond that, the proof looks OK.
 

1. What is the cardinality of the Cantor set?

The Cantor set has a cardinality of c, which is the same as the cardinality of the real numbers.

2. How is the Cantor set related to the real numbers?

The Cantor set is a subset of the real numbers, meaning that all elements of the Cantor set are also real numbers. However, the Cantor set does not contain all the real numbers.

3. How is the cardinality of the Cantor set determined?

The cardinality of the Cantor set is determined by the concept of "uncountability", meaning that the set cannot be put into a one-to-one correspondence with the natural numbers. This is proven through Cantor's diagonalization argument.

4. Can the cardinality of the Cantor set be visualized?

Yes, the Cantor set can be visualized as a fractal, with each iteration removing the middle third of the remaining line segments. As the iterations continue, the resulting set becomes increasingly dense and complex, illustrating its uncountable nature.

5. How does the cardinality of the Cantor set compare to other sets?

The cardinality of the Cantor set is the same as the cardinality of the real numbers, but it is smaller than the cardinality of the power set of the natural numbers (2aleph-null). This means that the Cantor set is larger than countable sets, but smaller than uncountable sets.

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