even no of triangles P_iP_jP_k containing interior P in convex n-gon
Source: 1983 Polish MO Finals p1
February 25, 2020
combinatorial geometrycombinatoricspolygonTriangles
Problem Statement
On the plane are given a convex -gon and a point inside it, not lying on any of its diagonals. Prove that if is even, then the number of triangles containing the point is even.