Claims

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2026_09_09_kruer_kohlmeyer: A Lean-checked permutation of the natural numbers with no four-term arithmetic progression at increasing or decreasing indices, certified by the bounty site Conjectures.io in September 2026; no refereed publication.

2026_09_11_ho: A permutation of the positive integers with no four-term arithmetic progression as a subsequence, grown from nested safe prefixes under a binary order; an arXiv preprint of September 2026 with a Lean formalization.

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