Add Erdős Problem 1171 (ω₁² multicolor partition)#3789
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henrykmichalewski wants to merge 3 commits intogoogle-deepmind:mainfrom
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Add Erdős Problem 1171 (ω₁² multicolor partition)#3789henrykmichalewski wants to merge 3 commits intogoogle-deepmind:mainfrom
henrykmichalewski wants to merge 3 commits intogoogle-deepmind:mainfrom
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Paul-Lez
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Apr 19, 2026
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Thanks for the contribution! A few comments:
Paul-Lez
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One tiny follow-up nit:
Per review on PR google-deepmind#3789: - Copyright year → 2026 - Add [Va99, 7.84] reference per Erdős citation policy - Use `answer(sorry) ↔` pattern for the open main theorem - Change `mono_k` category from `research solved` to `API` (local lemma) - Remove `baumgartner_under_MA` theorem — `True → …` was vacuous. Replaced with a block comment documenting the result as deferred until a faithful Lean predicate for Martin's Axiom is available. Assisted by Claude (Anthropic).
Mirrors the Round C docstring pass from the private repo's phase1-infrastructure branch. Each Lean file now carries the canonical source statement and upstream URL inline so reviewers can verify formalization against the source without navigating away from the diff.
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Problem
Erdős Problem 1171: https://www.erdosproblems.com/1171
Multicolor partition relation concerning ω₁² and open questions about which partition relations hold.
Contents
OrdinalMultiColorRamsey α β γ kdefinition generalizing the binary ordinal partition relation tok+1colorsCloses #1993
Assisted by Claude (Anthropic).