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Erdős–Szekeres conjecture on convex-position numbers

Prove that for every integer k ≥ 3, g(k) = 2^{k−2} + 1, where g(k) denotes the smallest integer such that any set of g(k) points in the plane in general position (with no three collinear) contains k points in convex position.

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Background

The Erdős–Szekeres problem asks for the minimum number g(k) such that any planar point set in general position of size g(k) contains k points in convex position. The exact values are known only for small k: g(4)=5, g(5)=9, and g(6)=17. Erdős and Szekeres proposed the formula g(k)=2{k−2}+1 and proved it as a lower bound, but the general case remains unproven. In this work, the authors use SAT-based encodings with rotational symmetry to find and classify symmetric extremal configurations for related instances, providing computational evidence and tools but not resolving the conjecture itself.

References

Erd\H{o}s and Szekeres conjectured that $g(k) = 2{k-2} + 1$ for every $k$, which matches the three known datapoints, and proved this to be a lower bound.

Automated Symmetric Constructions in Discrete Geometry (2506.00224 - Subercaseaux et al., 30 May 2025) in Section 1 (Introduction), Erdős–Szekeres paragraph