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Feynman on Fermat's Last Theorem (2016)

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Re: Feynman on Fermat's Last Theorem (2016)

#11
Previously discussed:

https://news.ycombinator.com/item?id=16041560

https://news.ycombinator.com/item?id=14940636

https://news.ycombinator.com/item?id=14355834

https://news.ycombinator.com/item?id=12018221

... and previously submitted without discussion:

https://news.ycombinator.com/item?id=17581023

https://news.ycombinator.com/item?id=15904199

Re: Feynman on Fermat's Last Theorem (2016)

#12
post #7
post #2

_DON'T DOWN VOTE JUST BECAUSE YOU CAN'T DO MATH_ The proof Fermat hinted to was about the difference between squares. All whole numbers taken to a power greater than two (n^3) can be represented as the difference between two whole squares (x^2 - y^2). These differences can then be shown as the sum of consecutive odd numbers: 2^3 = 3^2 - 1^2 = (1+3+5) - (1) = 8, 3^3 = 6^2 - 3^2 = (1+3+5+7+9+11) - (1+3+5) = 27, 4^3 = 1…

Sounds interesting, but not sure what you mean by: > you'll discover that there will always be a gap if you try and combine two odd number series together Can you elaborate?

ox_n's last theorem

Re: Feynman on Fermat's Last Theorem (2016)

#13
post #9
post #5

This proof (or "plausibility argument") bugs me so much. Just because something thins out and becomes rare doesn't mean it doesn't exist. As n gets bigger, the probability of n being a perfect square gets smaller and smaller. In the limit, the probability is zero. Does this mean square numbers don't exist?

This isn't a proof.

I know, but it's being exhibited as an example of how back-of-the-envelope type of approximations by physicists can be just as good as rigid mathematical thinking. And I don't find this to be a convincing example of how loose physicist arguments can work.

Schwartz distributions, infintesimals; okay, fine, those turned out to be a weird trick that can be formalised. But sometimes their tricks are just plain wrong and this is one example of a trick that just is wrong and can't be formalised.

Re: Feynman on Fermat's Last Theorem (2016)

#14
post #2

_DON'T DOWN VOTE JUST BECAUSE YOU CAN'T DO MATH_ The proof Fermat hinted to was about the difference between squares. All whole numbers taken to a power greater than two (n^3) can be represented as the difference between two whole squares (x^2 - y^2). These differences can then be shown as the sum of consecutive odd numbers: 2^3 = 3^2 - 1^2 = (1+3+5) - (1) = 8, 3^3 = 6^2 - 3^2 = (1+3+5+7+9+11) - (1+3+5) = 27, 4^3 = 1…

> The same trick works for higher powers.

can you demonstrate?

Re: Feynman on Fermat's Last Theorem (2016)

#15
post #2

_DON'T DOWN VOTE JUST BECAUSE YOU CAN'T DO MATH_ The proof Fermat hinted to was about the difference between squares. All whole numbers taken to a power greater than two (n^3) can be represented as the difference between two whole squares (x^2 - y^2). These differences can then be shown as the sum of consecutive odd numbers: 2^3 = 3^2 - 1^2 = (1+3+5) - (1) = 8, 3^3 = 6^2 - 3^2 = (1+3+5+7+9+11) - (1+3+5) = 27, 4^3 = 1…

Do you really believe that: (a) This constitutes a proof; (b) This is the "proof" that Fermat had; (c) Mathematicians missed this for over 350 year? I'm not quite sure exactly what you are claiming.

It's completely arrogant to assume that because it hasn't been solved by "better" people that I couldn't solve it.

Re: Feynman on Fermat's Last Theorem (2016)

#16
post #5

This proof (or "plausibility argument") bugs me so much. Just because something thins out and becomes rare doesn't mean it doesn't exist. As n gets bigger, the probability of n being a perfect square gets smaller and smaller. In the limit, the probability is zero. Does this mean square numbers don't exist?

By Feynman's argument, you can prove that square numbers almost certainly keep on existing.

Roughly, it goes as such:

1) the probability of N being a perfect square is proportional to 1/sqrt(N).

2) For any N_0 arbitrarily high, if you integrate from N_0 to infinity the expression (1/sqrt(N) dN), you get infinity.

3) The expression in 2) is the "Feynman equivalent" of the expected number of square numbers above N_0.

So Feynman's nonproof actually turns out to be true, despite it not being a proof in this case as well.

Re: Feynman on Fermat's Last Theorem (2016)

#17
post #4
post #2

_DON'T DOWN VOTE JUST BECAUSE YOU CAN'T DO MATH_ The proof Fermat hinted to was about the difference between squares. All whole numbers taken to a power greater than two (n^3) can be represented as the difference between two whole squares (x^2 - y^2). These differences can then be shown as the sum of consecutive odd numbers: 2^3 = 3^2 - 1^2 = (1+3+5) - (1) = 8, 3^3 = 6^2 - 3^2 = (1+3+5+7+9+11) - (1+3+5) = 27, 4^3 = 1…

> It's not that hard people. Stop believing everything you're told about how "hard" something is. There are still many problems in physics and mathematics which are considered "hard" (e.g., dark energy, Riemann hypothesis, etc). Can we crack them by simply adopting your positive mindset?

What other mindset do you see working better?

Re: Feynman on Fermat's Last Theorem (2016)

#18
post #14
post #2

_DON'T DOWN VOTE JUST BECAUSE YOU CAN'T DO MATH_ The proof Fermat hinted to was about the difference between squares. All whole numbers taken to a power greater than two (n^3) can be represented as the difference between two whole squares (x^2 - y^2). These differences can then be shown as the sum of consecutive odd numbers: 2^3 = 3^2 - 1^2 = (1+3+5) - (1) = 8, 3^3 = 6^2 - 3^2 = (1+3+5+7+9+11) - (1+3+5) = 27, 4^3 = 1…

> The same trick works for higher powers. can you demonstrate?

Yes.

x and y will be a multiple of the base number.

Re: Feynman on Fermat's Last Theorem (2016)

#19
post #7
post #2

_DON'T DOWN VOTE JUST BECAUSE YOU CAN'T DO MATH_ The proof Fermat hinted to was about the difference between squares. All whole numbers taken to a power greater than two (n^3) can be represented as the difference between two whole squares (x^2 - y^2). These differences can then be shown as the sum of consecutive odd numbers: 2^3 = 3^2 - 1^2 = (1+3+5) - (1) = 8, 3^3 = 6^2 - 3^2 = (1+3+5+7+9+11) - (1+3+5) = 27, 4^3 = 1…

Sounds interesting, but not sure what you mean by: > you'll discover that there will always be a gap if you try and combine two odd number series together Can you elaborate?

Consecutive base numbers will necessarily alternate between even and odd. So even the closest base numbers still have a gap between their resulting odd number series, which only increases as the distance between base numbers increases.

Re: Feynman on Fermat's Last Theorem (2016)

#20
post #15

Earlier quoted context omitted.

Do you really believe that: (a) This constitutes a proof; (b) This is the "proof" that Fermat had; (c) Mathematicians missed this for over 350 year? I'm not quite sure exactly what you are claiming.

It's completely arrogant to assume that because it hasn't been solved by "better" people that I couldn't solve it.

OK, so I'm taking it from your comment that you really do believe this constitutes a proof. Thanks for the reply.
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