DOTS EVERYWHERE
Source: 2017 USAMO #5
April 20, 2017
AMCUSA(J)MOUSAMO2017 USAMOHi
Problem Statement
Let denote the set of all integers. Find all real numbers such that there exists a labeling of the lattice points with positive integers for which: [*] only finitely many distinct labels occur, and
[*] for each label , the distance between any two points labeled is at least .Proposed by Ricky Liu