n coloured lattice points , same color with ther center of gravity, bw
Source: 11th QEDMO p5 Seniors (6-8. 12. 2012) https://artofproblemsolving.com/community/c1512515_qedmo_200507
May 16, 2021
latticeColoringcombinatoricscombinatorial geometry
Problem Statement
Let be a natural number and the set of points on the plane with integer coordinates. Every point in is colored now in one of the colors red or green. Show that there are different points all of which have the same color and whose center of gravity is also in and is of the same color.