This website contains problems from math contests. Problems and corresponding tags were obtained from the Art of Problem Solving website.

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Found problems: 1

2023 Serbia Team Selection Test, P6
Tags: combinatorial geometry , geometry , walls
There are $n^2$ segments in the plane (read walls), no two of which are parallel or intersecting. Prove that there are at least $n$ points in the plane such that no two of them see each other (meaning there is a wall separating them).