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Erdős problem 107

Let f(n)f(n) be minimal such that any f(n)f(n) points in R2ℝ^2, no three on a line, contain nn points which form the vertices of a convex nn-gon. Prove that f(n)=2n−2+1f(n) = 2^{n-2} + 1.

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The source's own material, retained exactly.

7 retained statements36c6d0fef71a

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FormalConjectures/ErdosProblems/

107.lean

Retained formal statement1 of 7

Let f(n)f(n) be minimal such that any f(n)f(n) points in R2ℝ^2, no three on a line, contain nn points which form the vertices of a convex nn-gon. Prove that f(n)=2n−2+1f(n) = 2^{n-2} + 1.

FormalConjectures/ErdosProblems/107.leanErdos107.erdos_1071 lineExact file
sorry ↔ ∀ n ≥ 3, Erdos107.f n = 2 ^ (n - 2) + 1
OpenStatement only, no proof