Combinatorics
Date added
$4,912 bounty1 piece from 1 personlast one last month
Nobody has attempted this. A complete proof or refutation takes the whole bounty.
A lemma, a definition, a special case. There is no race: when someone closes the problem, up to half of its bounty can go to the recognised pieces that led there.
contrib new erdos-949Command line, then a pull request on GitHub.
1 piece · 6 lemmas
23 Sept 2026
General Zorn criterion for 949 + solved cases: #S<c, S bounded above/below, span_Q S ≠ ⊤
5H4Cpb…vjBPNo · 6 lemmas
conjectures-tasks
The pinned statement, the Lean challenge file and the exact bundle you build against.
versions/fc-v2-erdos949-erdos-949-2fc2f306f341417c188803f3-formalized →
conjectures-contribution
Every published piece for this problem, with its Lean source and its signed record.
contributions/erdos-949 →
Formal statement
Proof target
import Mathlib
import FormalConjectures.ErdosProblems.«949»
import TaskSupport
namespace Bounty
theorem target : fcTypeOfName% "Erdos949.erdos_949" := by
sorry
end Bounty
Original conjecture (Lean type)
True ↔ ∀ (S : Set ℝ), (∀ a ∈ S, ∀ b ∈ S, a + b ∉ S) → ∃ A ⊆ Sᶜ, Cardinal.mk ↑A = Cardinal.continuum ∧ A + A ⊆ SᶜOriginal conjecture source: FormalConjectures/ErdosProblems/949.lean
References
Something wrong with this formalization?
A statement that does not faithfully capture the original conjecture is the one real risk here, so we would rather hear about it early - before someone spends weeks on it.
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