Circular chromatic number of flower graphs

摘要

Vince asked whether for each rationaL r between 2 and 4 there was a planar graph of circular chromatic number r. Moser aid Zhu showed that the answer is yes, the first for 2 < r < 3, the second for 3 < r < 4. This paper gives another family of planar graphs with circular chromatic number between 2 and 3.