Math information representations

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Discussion Overview

The discussion revolves around the representation of real numbers, particularly in the context of Cantor's diagonal argument and the implications for the countability of real numbers. Participants explore various interpretations of representations, the nature of open intervals, and the validity of Cantor's proof.

Discussion Character

  • Debate/contested
  • Mathematical reasoning
  • Conceptual clarification

Main Points Raised

  • Some participants propose that any two real numbers can form an open interval, while others challenge the notion of "noticeable" numbers and the concept of representation.
  • There is a claim that Cantor's diagonal argument relies on the assumption of a complete list of real numbers, which some argue cannot exist due to the lack of representation.
  • Participants discuss the meaning of "representation," suggesting methods such as base^power representation and equivalence classes of rational sequences.
  • Some participants express confusion about the implications of Cantor's proof, questioning how a complete list can be formed if it cannot represent all real numbers.
  • There are assertions that without sufficient input information, no valid conclusions can be drawn regarding the countability of real numbers.

Areas of Agreement / Disagreement

Participants generally disagree on the validity of Cantor's proof and the nature of representations of real numbers. Multiple competing views remain regarding the implications of these representations and the existence of a complete list of real numbers.

Contextual Notes

Limitations in the discussion include unclear definitions of "representation," assumptions about the completeness of lists of real numbers, and unresolved mathematical steps regarding the diagonal argument.

  • #31
Originally posted by Organic
No dear master_coda,

If the list is complete, then any R number must be in the list, therefore we cannot find any R number (by using Cantor's function) which is not in the list.

And we cannot find any output result (by using Cantor's function) which is not in the list, if and only if we have no input.

Question: And when we have no input?

Answer: When we have no way to represent the list.

Therefore when the R list is complete, we cannot represent it, and cannot conclude if it is uncountable XOR countable.

Without information we cannot prove anything about R numbers.

You don't even have a basic understanding of a proof by contradiction. The whole point of the a proof is that even though you can't find a real number not in the list, you can still find a real number not in the list.

When a proposition and it's negation are both true, you have a contradiction. That means that you are reasoning from a false premise. In this case, the premise is that it is possible to construct a complete list. You can't write a complete list of the reals because if you could, you could show that something is both true and false.
 
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  • #33
... Question: And when we have no input?

Answer: When we have no way to represent the list.

The correct answer is "When no such list exists."
 

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