Skip to content

Erdős problem 698

Is there some h(n)→∞h(n)\to \infty such that for all 2≤i<j≤n/22\leq i<j\leq n/2 gcd((ni),(nj))≥h(n)?\textrm{gcd}\left( \binom{n}{i},\binom{n}{j}\right) \geq h(n)?

Sources

The source's own material, retained exactly.

4 retained statements36c6d0fef71a

Open selected source

FormalConjectures/ErdosProblems/

698.lean

Retained formal statement1 of 4

Is there some h(n)→∞h(n)\to \infty such that for all 2≤i<j≤n/22\leq i<j\leq n/2 gcd((ni),(nj))≥h(n)?\textrm{gcd}\left( \binom{n}{i},\binom{n}{j}\right) \geq h(n)?

This was resolved by Bergman [Be11], who proved that for any 2≤i<j≤n/22\leq i<j\leq n/2 gcd((ni),(nj))≫n1/22ii3/2,\textrm{gcd}\left( \binom{n}{i},\binom{n}{j}\right) \gg n^{1/2}\frac{2^i}{i^{3/2}}, where the implied constant is absolute.

FormalConjectures/ErdosProblems/698.leanErdos698.erdos_6984 linesExact file
True ↔  ∃ h,    Filter.Tendsto h Filter.atTop Filter.atTop ∧      ∀ (n i j : ℕ), 2 ≤ i → i < j → j ≤ n / 2 → h n ≤ (n.choose i).gcd (n.choose j)
SolvedStatement only, no proof