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Research notes on every problem, and a library of the papers behind them. Built from the open erdos repository.

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Claims

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1978_01_01_harborth: Every set of 10 points in general position in the plane contains an empty convex pentagon, and some 9 points contain none, so g(5)=10g(5)=10.

1983_12_01_horton: Horton constructs arbitrarily large planar point sets in general position with no empty convex heptagon, so g(k)g(k) does not exist for k≥7k\ge7 and the question whether g(k)g(k) always exists is answered negatively.

2007_09_01_nicolas: Every sufficiently large set of points in general position in the plane contains an empty convex hexagon, so g(6)g(6) exists.

2007_09_11_gerken: Every set of points in general position in the plane that contains a convex 9-gon contains an empty convex hexagon, so g(6)g(6) exists and is at most 1717.

2024_03_01_heule_scheucher: A satisfiability proof that every set of 30 points in general position in the plane contains an empty convex hexagon; with Overmars's 29-point set this gives g(6)=30g(6)=30, the last value of g(k)g(k) that exists.