An Analogue of Hajós' Theorem for the Circular Chromatic Number (II)

Abstract.This paper designs a set of graph operations, and proves that for 2≤k/d<3, starting from Kk/d, by repeatedly applying these operations, one can construct all graphs G with χc(G)≥k/d. Together with the result proved in [20], where a set of graph operations were designed to construct graphs G with χc(G)≥k/d for k/d≥3, we have a complete analogue of Hajós' Theorem for the circular chromatic number.

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