| 有向图最小圈长不大于4的一个充分条件 |
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| 引用本文： | 梁浩,徐俊明.有向图最小圈长不大于4的一个充分条件[J].吉林大学学报(理学版),2013,51(2):241-243. |
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| 作者姓名： | 梁浩 徐俊明 |
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| 作者单位： | 1. 西南财经大学 经济数学学院, 成都 611130； 2. 中国科学技术大学 数学科学学院, 合肥 230026 |
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| 基金项目： | 国家自然科学基金(批准号:11071233;1272008) |
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| 摘 要： | 运用组合计数的方法, 给出了与Caccetta Haggkvist猜想有关的一个近似结果, 即给出最小出度至少为αn的n阶有向图含有长度不超过4的有向圈的充分条件： α≥0.288 66.
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| 关 键 词： | 有向图 有向圈 出度 定向三角形 充分条件 |
| 收稿时间： | 2012-06-06 |
A Sufficient Condition for Digraphs with Girth at Most 4 |
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| LIANG Hao,XU Jun-ming.A Sufficient Condition for Digraphs with Girth at Most 4[J].Journal of Jilin University: Sci Ed,2013,51(2):241-243. |
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| Authors: | LIANG Hao XU Jun-ming |
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| Institution: | 1. College of Mathematics, Southwestern University of Finance and Economics, Chengdu 611130, China;2. School of Mathematical Sciences, University of Science and Technology of China, Hefei 230026, China |
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| Abstract: | Using some combinatorial techniques, the authors gave an approximate result related to Caccetta Haggkvist conjecture, that is, a sufficient condition α≥0.288 66 for which any digraph on n vertices with minimum out degree at least αn contains a directed cycle of length at most 4. |
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| Keywords: | digraph directed cycle out degree transitive triangle sufficient condition |
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