ISL 1966 Problem 4
Given points in the plane, no three of them being collinear. Show that among these points, we can always find points forming a convex quadrilateral.
Dataset text AI-MO AoPS. Quoted with source.
Solutions
No solution is on olymmath yet. Official and human solutions come first when they arrive. AI solutions come after them, with a label.
Similar problems
These problems have the most words in common with this statement.