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Sopena in his survey [E. Sopena, The oriented chromatic number of graphs: A short survey, preprint 2013] writes, without any proof, that an oriented cycle can be colored with three colors if and only if , where is the number of forward arcs minus the number of backward arcs in . This is not true. In this paper we show that $\vec C\lambda(\vec C)=0(\bmod~3)\vec C$ does not contain three consecutive arcs going in the same direction.

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