All open problems
Source labels openChecked July 26, 2026

OtherCombinatorics

Beaver Math Olympiad (BMO): Set

BMO#2 formulation variant

Mathematical statement

BMO#2 formulation variant

Alternative statement of beaver_math_olympiad_problem_2_antihydra using set size comparison instead of a recurrent sequence b.

Statement source: Other statement material

Statement terms: Source-specific

Source-specific terms. Therefore does not assert reuse rights beyond attributed display.

Statement artifacts, not proofs

These records expose exact Lean propositions and statement-only wrappers. Defining a proposition does not supply a proof of it. A placeholder-bearing target also contains no proof. Elaboration checks syntax and types; it does not certify that a formalization perfectly captures every nuance of the informal problem.

Pinned Lean formulation 1

beaver_math_olympiad_problem_2_antihydra.variants.set

Canonical source
Complete statement target, proof intentionally absentLean 4
theorem beaver_math_olympiad_problem_2_antihydra.variants.set    (a :   ) (a_ini : a 0 = 8)    (a_rec :  n, a (n + 1) = (3 * a n) / 2) (n : ) :    ((Finset.Ico 0 n).filter fun x  Odd (a x)).card       2 * ((Finset.Ico 0 n).filter fun x  Even (a x)).card := by  sorry
Statement source
Formal Conjectures
Lean version
v4.27.0
Placeholder
Present; no proof artifact
Source evidence
Pinned source index
Fidelity review
Community formulation

References