A thought on the existence of an odd perfect number

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Discussion Overview

The discussion revolves around the existence of odd perfect numbers, exploring various approaches to proving their non-existence and the implications of such proofs. The scope includes theoretical considerations and mathematical reasoning related to number theory.

Discussion Character

  • Exploratory
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant suggests using proof by contradiction to assume the existence of an odd perfect number and questions the implications of the number of divisors of odd numbers.
  • Another participant references a Wikipedia article to indicate that there is substantial knowledge regarding odd perfect numbers.
  • A participant expresses curiosity about the lack of a prize for proving the existence or non-existence of odd perfect numbers.
  • It is proposed that an odd perfect number cannot be a square, which would lead to the sum of its true divisors being odd, supporting the argument against their existence.
  • One participant reflects on the nature of mathematical proofs, stating that proving non-existence is generally more challenging than proving existence, drawing parallels to complexity theory and number theory.
  • Another participant notes that the discussion of odd perfect numbers resonates with concepts in physics, particularly regarding exclusion limits.

Areas of Agreement / Disagreement

Participants express varying viewpoints on the existence of odd perfect numbers, with some suggesting they likely do not exist while others emphasize the complexity of proving such claims. No consensus is reached on the matter.

Contextual Notes

Participants mention various assumptions and implications regarding the properties of odd perfect numbers and their divisors, but these remain unresolved within the discussion.

Who May Find This Useful

Readers interested in number theory, mathematical proofs, and the philosophical aspects of existence in mathematics may find this discussion relevant.

MathematicalPhysicist
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Well the most obvious approach to prove that such a number doesn't exist is by ad absurdum, or so I think.
Assume there exists an odd perfect number ##2n+1##, then by definition ##2n = \sum_{m\ne 1, 2n+1, m|(2n+1)}m##.

So, since m is odd (since 2n+1 is odd and it divides it), if you can prove that the sum has an odd number of terms then obviously we get a contradiction.
What is known of the number of divisors of an odd number?
 
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The prize is immortality in the mathematical literature.
An odd perfect number cannot be a square. That alone is sufficient to make the sum of true divisors odd, so that's everything you get with that approach.
 
This is the great thing about mathematics. An odd perfect number probably doesn't even exist, but we know a lot about it!
 
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Vanadium 50 said:
This is the great thing about mathematics. An odd perfect number probably doesn't even exist, but we know a lot about it!
I prefer to phrase this in a positive way: Proofs of non-existence are much, much harder than proofs of existence. That's why lower bounds in complexity theory (NP=P), and those in number theory, e.g. FLT, are so incredibly complicated. Existence is often very easy: prove there is a group, ring, algebra, vector space: ##\{0\}##. Job done.
 
Vanadium 50 said:
This is the great thing about mathematics. An odd perfect number probably doesn't even exist, but we know a lot about it!
It sounds very familiar once you use physics jargon: Mathematicians set many exclusion limits.
 

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