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 Pengkuan December 3rd, 2015 03:41 AM

Cardinality of the set of binary-expressed real numbers

This article gives the cardinal number of the set of all binary numbers by counting its elements, analyses the consequences of the found value and discusses Cantor's diagonal argument, power set and the continuum hypothesis.
1. Counting the fractional binary numbers
2. Fractional binary numbers on the real line
3. Countability of BF
4. Set of all binary numbers, B
5. On Cantor's diagonal argument
6. On Cantor's theorem
7. On infinite digital expansion of irrational number
8. On the continuum hypothesis

Cardinality of the set of binary-expressed real numbers
PengKuan on Maths: Cardinality of the set of binary-expressed real numbers
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 CRGreathouse December 3rd, 2015 07:44 AM

Your proof in section 1 is incorrect -- you can't assume that set cardinalities will behave like exponents in the limit, despite the suggestive notation. (The result is correct, though.)

Your claim in section 2, explored in section 3, is incorrect. The set you actually work with is the dyadic rationals, but you conflate them with the set of fractional binary numbers (your $\mathbf{B_F}$, i.e., the set of real numbers between 0 and 1, which you choose to represent in binary).

Section 4 is incorrect by virtue of relying on the incorrect result from sections 2 and 3. Section 5 consists of a proof by assertion. Section 6, like section 4, relies on incorrect results and hence is also wrong. I did not bother checking further.

Review: Is this a mathematical breakthrough?

 Country Boy December 4th, 2015 08:43 AM

Surely you understand that the "number of real numbers" in a given interval does NOT depend upon how the numbers are expressed? So I don't understand your reference to "binary expressed numbers" and "binary numbers".

 Pengkuan December 8th, 2015 09:01 AM

Quote:
 Originally Posted by CRGreathouse (Post 467325) Your proof in section 1 is incorrect -- you can't assume that set cardinalities will behave like exponents in the limit, despite the suggestive notation. (The result is correct, though.) Your claim in section 2, explored in section 3, is incorrect. The set you actually work with is the dyadic rationals, but you conflate them with the set of fractional binary numbers (your $\mathbf{B_F}$, i.e., the set of real numbers between 0 and 1, which you choose to represent in binary). Section 4 is incorrect by virtue of relying on the incorrect result from sections 2 and 3. Section 5 consists of a proof by assertion. Section 6, like section 4, relies on incorrect results and hence is also wrong. I did not bother checking further. Review: Is this a mathematical breakthrough?
Thank you for checking my article. I'm sorry to have replied late. I'm not alerted by email of your message.

 Pengkuan December 8th, 2015 09:05 AM

Quote:
 Originally Posted by Country Boy (Post 468716) Surely you understand that the "number of real numbers" in a given interval does NOT depend upon how the numbers are expressed?
Yes.
Quote:
 Originally Posted by Country Boy (Post 468716) So I don't understand your reference to "binary expressed numbers" and "binary numbers".
I thought the set of binary numbers in the unit interval contains irrationals. It turned out no. Because when the number of digits goes to infinity, the digits are not actually infinite many.

 v8archie December 8th, 2015 10:06 AM

Quote:
 Originally Posted by Pengkuan (Post 474953) Because when the number of digits goes to infinity, the digits are not actually infinite many.
Marvellous! I do applaud your willingness to suspend preconceptions when dealing with the infinite, but not all counterintuitive results are correct.
Quote:
 Originally Posted by Pengkuan (Post 474953) I thought the set of binary numbers in the unit interval contains irrationals.
It does.

There is no such thing as "a binary number". Any real number is expressible in decimal, binary or any other base you care to name (as long as you allow me to have infinite strings of numbers). Rather neatly, if you choose any rational base, the set of numbers that you can't express without recourse to infinite strings of numbers is the same (here I am making use of notations like $13 \div 22 ={13 \over 22}= 0.5\dot0\dot9=0.5090909\ldots$ all of which are finite representations as is the equivalent binary fraction $0.\dot1000001001010011110\dot0$).

So your use of binary is completely redundant and flawed.

 Pengkuan September 16th, 2018 03:44 AM

Analysis of the proof of Cantor's theorem

Analysis of the proof of Cantor's theorem
Cantor's theorem states that the power set of ℕ is uncountable. This article carefully analyzes this proof to clarify its logical reasoning

PDF Analysis of the proof of Cantor's theorem PengKuan on Maths: Analysis of the proof of Cantor's theorem

 skipjack September 17th, 2018 02:13 AM

13/22 = 0.590909090..., whereas 0.509090909... is the expansion of 28/55.

 Pengkuan September 17th, 2018 11:47 AM

Quote:
 Originally Posted by skipjack (Post 599019) 13/22 = 0.590909090..., whereas 0.509090909... is the expansion of 28/55.
Yes. But they do not have the same binary expressions.

 skipjack September 18th, 2018 12:22 AM

Your analysis of Cantor's theorem doesn't seem to quote any part of Cantor's proof of it.

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