- #1

alpha_michi

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for a²+b²:

for b²+c²:

https://www.physicsforums.com/attachments/284600

for a²+b²+c²:

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- A
- Thread starter alpha_michi
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- #1

alpha_michi

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for a²+b²:

for b²+c²:

https://www.physicsforums.com/attachments/284600

for a²+b²+c²:

- #2

alpha_michi

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SORRY here:

- #3

Office_Shredder

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Anyway, you forgot one of the face diagonals. ##\sqrt{975^2+264^2}## is not an integer.

- #4

alpha_michi

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Ok, I will try that one too.

Anyway, you forgot one of the face diagonals. ##\sqrt{975^2+264^2}## is not an integer.

- #5

jedishrfu

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- #6

aheight

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A suite of optimized computer programs was designed to systematically search for a perfect cuboid, keep track of close misses, and investigate the statistical trend of these near matches with increasing Euler brick size. While no perfect cuboid was found, the minimum length of the odd side has been substantially extended from the prior published limit of 3 trillion1 (3 x 10^12) to 25 trillion (2.5 x 10^13), and the minimum side has increased from the prior published limit of 10 billion2 (10^10) to 500 billion (5 x 10^11 ).

The author concludes:

This seems naive to suggest after only checking a basically insignificant number of cases, i.e., there may be one that has extremely large faces. Why would he make what I consider to be a foolish claim?While some interesting near-misses have been identified, the overall trend with increasing minimum side does not favor the existence of a perfect cuboid.

- #7

jedishrfu

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While it’s truly a small percentage of an infinitude of possible numbers, I suspect a sequence of solutions indicates that the near misses are happening less often and perhaps with greater differences in the near miss category that indicates we may never find a solution.

Also I’m sure they’ve published a paper somewhere that describes the background of their conclusion and it would be worthwhile to investigate further.

- #8

pbuk

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Yes, this is the paper linked and quoted from in #6 and this does indeed describe two reasons for Matson's claim which @aheight seems to have overlooked:Also I’m sure they’ve published a paper somewhere that describes the background of their conclusion and it would be worthwhile to investigate further.

A perhaps more telling trend is the plot of least-significant matching bit (where all higher bits match). As X increases, the point of Y2 mismatch (reading from most-significant to least-significant bit) is rising at nearly the same rate as the number of bits in X. This trend suggests that it is highly unlikely that there is a perfect cuboid.

and

A plot of the results for the even side X cases up to 200 billion is shown below, followed by the corresponding plot of least-significant matching bit (where all higher bits match). As with the odd side plot, the point of Y2 mismatch is rising at about the same rate as the number of bits in X, again suggesting poor odds that there is a perfect cuboid.

- #9

jedishrfu

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Basically, I generated a table of squares, to create a table of Pythagorean triples and then started a search for matching triples ie ones with common square components.

It was a fun project, but of course the iPad could never compete with a super computer in searching a vast range of possibilities.

- #10

aheight

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Ok, thanks for that. Sorry I missed it. I'm not a Number theorist but am personally skeptical we can predict the future behavior of diophantine expressions based on the previous results of those expressions. My understanding is that integer arithmetic does not work this way. Rather it is discontinuous and often involves abrupt changes. For example a number N can have a hundred factors but N+1 can be prime. Is this a flawed understanding?Yes, this is the paper linked and quoted from in #6 and this does indeed describe two reasons for Matson's claim which @aheight seems to have overlooked:

A perhaps more telling trend is the plot of least-significant matching bit (where all higher bits match). As X increases, the point of Y2 mismatch (reading from most-significant to least-significant bit) is rising at nearly the same rate as the number of bits in X. This trend suggests that it is highly unlikely that there is a perfect cuboid.

and

A plot of the results for the even side X cases up to 200 billion is shown below, followed by the corresponding plot of least-significant matching bit (where all higher bits match). As with the odd side plot, the point of Y2 mismatch is rising at about the same rate as the number of bits in X, again suggesting poor odds that there is a perfect cuboid.

- #11

pbuk

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Yes this is a flawed understanding: in fact the more factors that N has the more likely N + 1 is to be prime.

What we have here is like looking for two touching needles in an ever-growing series of haystacks. If, as in this case, the larger the haystacks the further apart the closest pair of needles are then it suggests (only suggests mind, not anything stronger) that there is a low probability (only a low probability mind, not anything stronger) that we will ever find a haystack with two touching needles.

It is true that there are some surprising results in number theory, but these do not usually reverse trends such as these, rather they are like looking for needles in a series of increasingly large haystacks and not finding any until the ## 10^{10^{10}} th ## haystack which contains a whole sewing set already threaded with thread the colours of the rainbow in order!

What we have here is like looking for two touching needles in an ever-growing series of haystacks. If, as in this case, the larger the haystacks the further apart the closest pair of needles are then it suggests (only suggests mind, not anything stronger) that there is a low probability (only a low probability mind, not anything stronger) that we will ever find a haystack with two touching needles.

It is true that there are some surprising results in number theory, but these do not usually reverse trends such as these, rather they are like looking for needles in a series of increasingly large haystacks and not finding any until the ## 10^{10^{10}} th ## haystack which contains a whole sewing set already threaded with thread the colours of the rainbow in order!

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