ELMO 2010 Problem 1
Determine all (not necessarily finite) sets of points in the plane such that given any four distinct points in , there is a circle passing through all four or a line passing through some three.
Carl Lian.
Dataset text AI-MO AoPS. Quoted with source.
Official text: ELMO 2010 official paper, page 1.
Also ELMO SL 2010 G5.
Solutions
No solution is on olymmath yet. Official and human solutions come first when they arrive. AI solutions come after them, with a label.
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