Plane figure with area > n can cover n + 1 lattice points
Source: Mediterranean MO 1999
October 11, 2012
geometrypigeonhole principleanalytic geometrycombinatorics unsolvedcombinatorics
Problem Statement
A plane figure of area is given, where is a positive integer. Prove that
this figure can be placed onto a Cartesian plane so that it covers at least
points with integer coordinates.