MathDB
Convex polygons

Source: Balkan MO 2007

April 28, 2007
floor functiongeometrygeometric transformationrotationcombinatorial geometrycombinatorics unsolvedcombinatorics

Problem Statement

For a given positive integer n>2n >2, let C1,C2,C3C_{1},C_{2},C_{3} be the boundaries of three convex nn- gons in the plane , such that C1C2,C2C3,C1C3C_{1}\cap C_{2}, C_{2}\cap C_{3},C_{1}\cap C_{3} are finite. Find the maximum number of points of the sets C1C2C3C_{1}\cap C_{2}\cap C_{3}.