Cardinality of the set of binary-expressed real numbers

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Discussion Overview

The discussion revolves around the cardinality of the set of binary-expressed real numbers, examining concepts such as Cantor's diagonal argument, the power set, and the continuum hypothesis. Participants analyze the implications of cardinality in the context of fractional binary numbers and challenge the reasoning presented in an article regarding these topics.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants assert that the reasoning in the article regarding the transition from ##2^n## fractional numbers to ##2^{\aleph_0}## is incorrect, claiming that cardinalities do not behave in that manner.
  • Others suggest that there are significant errors in the article, recommending a specific book on set theory for better understanding.
  • One participant emphasizes the need for a precise identification of errors in Cantor's diagonal argument rather than vague analogies, pointing to a rigorous proof of the uncountability of the reals.
  • Another participant argues that the reasoning presented in the article demonstrates a lack of understanding of set theory, particularly in proof by contradiction.
  • There is a discussion about the Grand Hotel analogy, with one participant clarifying that the argument for accommodating additional guests is simpler than described and does not relate directly to Cantor's diagonal argument.

Areas of Agreement / Disagreement

Participants express disagreement regarding the validity of the reasoning in the article, with multiple competing views on the interpretation of cardinality and Cantor's arguments. The discussion remains unresolved as participants challenge each other's claims without reaching consensus.

Contextual Notes

Participants highlight limitations in the article's reasoning and the need for precise definitions and logical steps in set theory. The discussion reflects varying levels of understanding and interpretation of cardinality concepts.

PengKuan
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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

Please read the article at
Cardinality of the set of binary-expressed real numbers
http://pengkuanonmaths.blogspot.com/2015/12/cardinality-of-set-of-binary-expressed.html
or
https://www.academia.edu/19403597/Cardinality_of_the_set_of_binary-expressed_real_numbers
 
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Sorry, it's wrong. You say there are ##2^n## "fractional numbers" with ##n## decimals. Correct so far. But then you say "let ##n## go to infinity and you obtain ##2^{\aleph_0}##". This is an incorrect reasoning. Cardinalities do not work like this.

There are other very obvious errors in your paper. I suggest to pick up the excellent book "Introduction to set theory" by Hrbacek and Jech and work through it carefully.

Also, if you claim to have found an error in Cantor's diagonal argument, then it is not ok to make some kind of analogy with the Hilbert grand Hotel. Instead, you need to specify where exactly the error is. In particular, here is the complete rigorous proof of "the reals are uncountable" http://us.metamath.org/mpegif/ruc.html Every single logical step is detailed from the axioms. You need to say exactly which step is not allowed and why. Otherwise, nobody will take you seriously.
 
micromass said:
Sorry, it's wrong. You say there are ##2^n## "fractional numbers" with ##n## decimals. Correct so far. But then you say "let ##n## go to infinity and you obtain ##2^{\aleph_0}##". This is an incorrect reasoning. Cardinalities do not work like this.

There are other very obvious errors in your paper. I suggest to pick up the excellent book "Introduction to set theory" by Hrbacek and Jech and work through it carefully.

Also, if you claim to have found an error in Cantor's diagonal argument, then it is not ok to make some kind of analogy with the Hilbert grand Hotel. Instead, you need to specify where exactly the error is. In particular, here is the complete rigorous proof of "the reals are uncountable" http://us.metamath.org/mpegif/ruc.html Every single logical step is detailed from the axioms. You need to say exactly which step is not allowed and why. Otherwise, nobody will take you seriously.
Thank for replying so fast.

I have given detailed my reasoning about diagonal argument after the Grand hotel. I will read your link.
 
PengKuan said:
Thank for replying so fast.

I have given detailed my reasoning about diagonal argument after the Grand hotel. I will read your link.

Well, your reasoning is wrong in any case and shows you do not really grasp set theory well. In particular, the proof by contradiction.
 
PengKuan said:
Thank for replying so fast.

I have given detailed my reasoning about diagonal argument after the Grand hotel. I will read your link.
I might be restating what micromass already said, but in your example of the Grand Hotel, to find a room for one more guest, all that needs to happen is that each current guest gets moved from room N to room N + 1 (where ##N \ge 1##), thereby freeing up room 1. The new guest can be assigned that room (room 1). The argument is a lot simpler than what you have described, and has nothing to do with Cantor's diagonal argument.

A similar argument can be used to accommodate any finite number of guests, simply by shifting each current occupant from room N to room N + k, where k is the number of new arrivals. The hotel can also accommodate a (countably) infinite number of new guests, by shifting each current occupant from room N to room 2N, thereby freeing up rooms 1, 3, 5, ..., 2N + 1, ... for the new arrivals.
 

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