A sufficient condition for a digraph to be positive-round

作者：Li Ruijuan^*; Zhang Xinhong; Meng Wei

来源：Optimization, 2008, 57(2): 345-352.

DOI：10.1080/02331930701780003

• positive-round digraph
• locally in-semicomplete digraph
• ordinary cycle

In 1999, Huang (Australas. J. Combin., 19, 203-208) proved that every round digraph is locally semicomplete, and characterized the round digraph. In this paper, a generalization of the round digraph, the positive-round digraph, is introduced. We note that positive-round digraphs form subclasses of the class of locally in-semicomplete digraphs and give a sufficient condition, so that a strong locally in-semicomplete digraph is positive-round. Immediately, we obtain a characterization of strong positive-round local in-tournaments.

• 出版日期2008
• 单位太原科技大学; 山西大学