MathDB
Turkey NMO 2010 P6

Source:

December 15, 2010
inequalitiesanalytic geometryemailcombinatorics proposedcombinatorics

Problem Statement

Let KK be the set of all sides and diagonals of a convex 2010āˆ’gon2010-gon in the plane. For a subset AA of K,K, if every pair of line segments belonging to AA intersect, then we call AA as an intersecting set. Find the maximum possible number of elements of union of two intersecting sets.