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Period-doubling prefix palindromic length is not 2-regular

The exact period-doubling conjecture is proved: d(n)=P(n+1)−P(n) is not 2-automatic and P is not 2-regular. The proof uses a marker C(n) recording a singleton 1 in some globally optimal factorization. A Gray-code independent-set bound gives nonnegative palindrome-edge slack. Uniform constructions and an all-path diagonal obstruction distinguish infinitely many binary prefixes for C. The sole computer-assisted lemma is an all-length local inclusion proved by complete reachable-state closure, independently implemented twice; finite value tests are not its proof. This does not provide a full closed formula for P or settle the separate Fibonacci conjecture. Classical palindrome structure, automatic-sequence closure and state distinguishability, and the source regularity/difference equivalence are credited. Worldwide priority remains unassessed.

Exact FrontierDelta

Prior state unknown→proved

Scope and record

Occurred: Oct 4, 2026

Delta type: SOURCE CLAIM

Assumptions: VibeMathed verification: unreviewed. Publication: announcement. AI contribution: ai-discovered. VibeMathed editorial classifications, scores, notes, relations, and dataset structure are CC BY 4.0. Source statements and linked content retain their own rights.

Canonical aliases: Period-doubling prefix palindromic length is not 2-regular · Period-doubling nonregularity

Confidence: Not scored

Registry verification: unreviewed · announcement · candidate

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VibeMathed
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OpenAI assistant (dot; underlying model unspecified)
model · ai model contributor · OpenAI

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Original conjecture, arXiv v2 evidence for this event

The exact period-doubling conjecture is proved: d(n)=P(n+1)−P(n) is not 2-automatic and P is not 2-regular. The proof uses a marker C(n) recording a singleton 1 in some globally optimal factorization. A Gray-code independent-set bound gives nonnegative palindrome-edge slack. Uniform constructions and an all-path diagonal obstruction distinguish infinitely many binary prefixes for C. The sole computer-assisted lemma is an all-length local inclusion proved by complete reachable-state closure, independently implemented twice; finite value tests are not its proof. This does not provide a full closed formula for P or settle the separate Fibonacci conjecture. Classical palindrome structure, automatic-sequence closure and state distinguishability, and the source regularity/difference equivalence are credited. Worldwide priority remains unassessed. parent of this event

Period-doubling prefix palindromic length is not 2-regular parent of this event

This event attributed to OpenAI assistant (dot; underlying model unspecified)

VibeMathed record: Period-doubling prefix palindromic length is not 2-regular evidence for this event

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