论文标题
四个块周期C（K，1,1,1）
Four Blocks Cycles C(k,1,1,1) in Digraphs
论文作者
论文摘要
一个四个块循环C（K1，K2，K3，K4）是由四个内部脱节的指向长度K1，K2，K2，K3和K4的联合形成的定向循环。 El Mniny证明，如果D是具有跨度t的digraph，而没有C（K，1，1，1）的细分，则D的色度最多为8^{3} k。在本文中，我们将把它提高到18k。
A four blocks cycle C(k1,k2,k3,k4) is an oriented cycle formed by the union of four internally disjoint directed paths of lengths k1,k2,k3 and k4 respectively. El Mniny proved that if D is a digraph having a spanning out-tree T with no subdivisions of C(k, 1, 1, 1), then the chromatic number of D is at most 8^{3}k. In this paper, we will improve this bound to 18k.
