The study of graph colouring has long been a central topic in discrete mathematics, with a prominent focus on optimising the assignment of labels or colours to vertices such that adjacent vertices are ...

This paper proves that for any integer n ≥ 4 and any rational number r, 2 ≤ r ≤ n — 2, there exists a graph G which has circular chromatic number r and which does not contain Kn as a minor. Journal ...