MathDB
cover all grid points by an infinite family of discs

Source: USAMO 2007

April 26, 2007
geometrycombinatoricsUSAMOcombinatorial geometrySoddy

Problem Statement

A square grid on the Euclidean plane consists of all points (m,n)(m,n), where mm and nn are integers. Is it possible to cover all grid points by an infinite family of discs with non-overlapping interiors if each disc in the family has radius at least 55?