From: John Jones on 27 Mar 2010 23:26 Frederick Williams wrote: > John Jones wrote: >> That old mathematical chestnut - "x cubed + y cubed = z cubed" >> seemed to be a historical problem for mathematicians. I'm not even sure >> if it has been proved yet. > > What precisely? Is the problem to find real numbers x, y, z such that x > cubed + y cubed = z cubed, or is it to find positive integers x, y, z > such that x cubed + y cubed = z cubed, or something else? > I don't think real numbers are a possibility. The problem is portrayed in the standard way.
From: John Jones on 27 Mar 2010 23:29 Niklasro(.appspot) wrote: > On Mar 26, 11:04 pm, John Jones <jonescard...(a)btinternet.com> wrote: >> That old mathematical chestnut - "x cubed + y cubed = z cubed" >> seemed to be a historical problem for mathematicians. I'm not even sure >> if it has been proved yet. >> Of course, the proof of "x cubed + y cubed = z cubed" isn't difficult. >> It's just that in a universe of an infinite number of proofs, we don't >> know where to find the proof we want. >> Why is this? There are no rules for finding proofs. Proofs aren't >> sequenced like numbers. Proofs are all jumbled together. Unlike numbers, >> there are no convenient Peano-type axioms for ordering and finding proofs. >> >> THE PROOF of x cubed + y cubed = z cubed------- >> >> "x cubed + y cubed = z cubed" is the answer, or solution to the proof >> that we need to find. >> "x cubed + y cubed = z cubed" is the starting condition. >> >> IF >> "x cubed + y cubed = z cubed" is both theorem (starting condition or >> question) and solution (answer), >> THEN >> proof is assured. >> >> BUT IF >> "x cubed + y cubed = z cubed" is theorem (question) and not a solution THEN >> proof is meaningless because "x cubed + y cubed = z cubed" is >> necessarily neither theorem nor solution. That is, a theorem is a >> vacuous notion in that it can be both present and absent. >> >> THE JOHN JONES CONCLUSION >> When asking for a proof, the first thing we need to do is ask whether we >> have a theorem or equation to prove, and not just a selection of empty >> marks or signs that only seem to look mathematical. >> >> But here's the pinch. A proof, in principle, must illustrate the >> difference between a vacuous mark and a semiotic indice (mathematical >> sign). How does a proof do that? >> >> Come on then you mathematicians, let's have the answer. > Obvious 2 methods are > 1. Induction You can't INDUCE that a sign is or isn't a mathematical or logical sign! > or > 2. Assume it's false and deduce a contradiction. Falsehood isn't expressed by mere marks or signs, nor can such signs be inductively or deductively proved. > Say method 1 or 2 works. Must then both?
From: Niklasro(.appspot) on 28 Mar 2010 05:57 On Mar 28, 3:29 am, John Jones <jonescard...(a)btinternet.com> wrote: > Niklasro(.appspot) wrote: > > On Mar 26, 11:04 pm, John Jones <jonescard...(a)btinternet.com> wrote: > >> That old mathematical chestnut - "x cubed + y cubed = z cubed" > >> seemed to be a historical problem for mathematicians. I'm not even sure > >> if it has been proved yet. > >> Of course, the proof of "x cubed + y cubed = z cubed" isn't difficult. > >> It's just that in a universe of an infinite number of proofs, we don't > >> know where to find the proof we want. > >> Why is this? There are no rules for finding proofs. Proofs aren't > >> sequenced like numbers. Proofs are all jumbled together. Unlike numbers, > >> there are no convenient Peano-type axioms for ordering and finding proofs. > > >> THE PROOF of x cubed + y cubed = z cubed------- > > >> "x cubed + y cubed = z cubed" is the answer, or solution to the proof > >> that we need to find. > >> "x cubed + y cubed = z cubed" is the starting condition. > > >> IF > >> "x cubed + y cubed = z cubed" is both theorem (starting condition or > >> question) and solution (answer), > >> THEN > >> proof is assured. > > >> BUT IF > >> "x cubed + y cubed = z cubed" is theorem (question) and not a solution THEN > >> proof is meaningless because "x cubed + y cubed = z cubed" is > >> necessarily neither theorem nor solution. That is, a theorem is a > >> vacuous notion in that it can be both present and absent. > > >> THE JOHN JONES CONCLUSION > >> When asking for a proof, the first thing we need to do is ask whether we > >> have a theorem or equation to prove, and not just a selection of empty > >> marks or signs that only seem to look mathematical. > > >> But here's the pinch. A proof, in principle, must illustrate the > >> difference between a vacuous mark and a semiotic indice (mathematical > >> sign). How does a proof do that? > > >> Come on then you mathematicians, let's have the answer. > > Obvious 2 methods are > > 1. Induction > > You can't INDUCE that a sign is or isn't a mathematical or logical sign! > > > or > > 2. Assume it's false and deduce a contradiction. > > Falsehood isn't expressed by mere marks or signs, nor can such signs be > inductively or deductively proved. > > > Say method 1 or 2 works. Must then both? OK: You assume there is no language. Say you have a lagnuage. Then both methods are perfectly valid. Modus tollens and unduction.
From: Niklasro(.appspot) on 28 Mar 2010 05:58 On Mar 27, 2:03 am, "Jesse F. Hughes" <je...(a)phiwumbda.org> wrote: > John Jones <jonescard...(a)btinternet.com> writes: > > It's just that in a universe of an infinite number of proofs, we don't > > know where to find the proof we want. > > Why is this? There are no rules for finding proofs. Proofs aren't > > sequenced like numbers. Proofs are all jumbled together. > > Yes! Yes! Now I understand it. > > This must indeed be why finding proofs is tough. There's simply no > way to order them. > > I see now that you *are* the resident Goedel expert after all. > > -- > "But what if I'm right [and have solved the factoring problem]? And > what if I can't contain the problem and, oh, in six months from now, > you are desperately trying to find food as you run from humans who > have turned to cannibalism to survive?" -- James S. Harris (2/21/09) There are rules for proving. Modus ponens, modus tollens, inductions...
From: Frederick Williams on 28 Mar 2010 07:22 John Jones wrote: > > Frederick Williams wrote: > > John Jones wrote: > >> That old mathematical chestnut - "x cubed + y cubed = z cubed" > >> seemed to be a historical problem for mathematicians. I'm not even sure > >> if it has been proved yet. > > > > What precisely? Is the problem to find real numbers x, y, z such that x > > cubed + y cubed = z cubed, or is it to find positive integers x, y, z > > such that x cubed + y cubed = z cubed, or something else? > > > > I don't think real numbers are a possibility. The problem is portrayed > in the standard way. So you think that this problem: Are there positive integers x, y, z such that x cubed + y cubed = z cubed? has not been solved? -- I can't go on, I'll go on.
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