Chromatic numbers of integer distance graphs Original Research Article

An integer distance graph is a graph G(D) with the set of integers as vertex set and with an edge joining two vertices u and v if and only if |u−v|∈D where D is a subset of the positive integers. We determine the chromatic number χ(D) of G(D) if D is a 4-element set of the form D={x,y,x+y,y−x}, x