IMO 2013 Shortlist C2
In the plane, 2013 red points and 2014 blue points are marked so that no three of the marked points are collinear. One n...
Category: Combinatorics
Problem
In the plane, 2013 red points and 2014 blue points are marked so that no three of the marked points are collinear. One needs to draw k lines not passing through the marked points and dividing the plane into several regions. The goal is to do it in such a way that no region contains points of both colors. Find the minimal value of k such that the goal is attainable for every possible configuration of 4027 points. (Australia)