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> [1729] is a very interesting number; it is the smallest number expressible as a sum of two cubes in two different ways. This isn’t actually correct. 1729 is
by JimDabell 4y ago
> [1729] is a very interesting number; it is the smallest number expressible as a sum of two cubes in two different ways.
This isn’t actually correct. 1729 is the smallest number expressible as a sum of two positive cubes in two different ways. The smallest number expressible as a sum of two cubes in two different ways is 91 (3^3+4^3 and -5^3+6^3).
- psychoslave 4y agoIs that still true with complex or higher dimension numbers in general? +832375400086541 if you can provide a proof through mathematical induction.
- renewiltord 4y agoThere's no total order on complex numbers, so what would smallest mean there? The numbers z=x+iy (x,y in Z) with smallest positive |z|? Fair enough.
- Y_Y 4y agoYou make an important point, but I understood the parent as, "what is the smallest integer expressible as the sum of two cubes of Cayley-Dickson algebras of order n?" So you're allowed to use complex/quaternions etc. in the cubes, but the number has to come from those well-ordered integers.
- ouid 4y ago>theres no total order on the complex numbers Sure there is, lex order on Re and Im and then inherit from the reals.
- renewiltord 4y ago> The smallest number expressible as a sum of two cubes in two different ways is 91 (3^3+4^3 and -5^3+6^3). That can't be true either since -91 = (-3)^3 + (-4)^3 and -91 = 5^3 + (-6)^3. Since -91 < 91, the statement has to be false. In fact, it is not the number x with smallest value |x| that can be expressed as the sum of two cubes in two different ways since, 0 = (-1)^3 + 1^3 and 0 = (-2)^3 + 2^3. It appears that 91 is the smallest positive integer that can be expressed as a sum of two cubes in two different ways. There is no value to this comment. I mostly just wanted to be annoying. I hope I'm right, at least.
- yrdmb 4y ago> There is no value to this comment. There is always value in truthful statements. You are right that 91 is not the smallest number as was implied by the parent. -91 is. After all it was the parent who brought in the negative integers into the mix.
- Y_Y 4y ago> There is always value in truthful statements. As long as we're not talking about nonzero value. I think GP made a worthwhile point, but in general the universe is full of uninteresting truths. Like take two large, distinct numbers, assert that they are unequal. Is that specific truth valuable?
- ttctciyf 4y ago> There is no value to this comment. I mostly just wanted to be annoying Since annoying provides negative value, your statement is incorrect.
- renewiltord 4y agoOh no! Hoist by my own petard of pedanticity! XD