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Single-fold Diophantine representations
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Skills:logic, thinking really hard Levels:1
Category:Mathematical logic Lean version:YES! ✔
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Single-fold Diophantine representations and undecidability under an at-most-one-solution promise. Every recursively enumerable set of tuples of natural numbers has a Diophantine representation with exactly one auxiliary solution for each member and none for nonmembers. This proves the single-fold conjecture and hence the finite-fold conjecture. Diophantine solvability over the nonnegative integers remains undecidable even with an at-most-one-solution promise.

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released 2026-09-24  |  1 theorem · 6 lemmas · 13 proofs · 11,310 words  |  PLAY LEVEL 1 »  (pdf)
Every recursively enumerable set of natural-number tuples has a polynomial Diophantine representation with exactly one complete auxiliary tuple for each member. This proves the single-fold conjecture and, consequently, the finite-fold conjecture.

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