【摘要】 本文讨论了有向联系系统与拟阵以及有向拟阵(ditroid)之间的关系,将A.Schrijver关于拟阵与联系系统的两个重要结果推广到有向情形。给出了判别有向联系系统的两个充要条件。更多还原

【Abstract】 The relationships beteween directed linking systems and matroids and ditroids are investigated. Two important results about matroids and lin- king systems of A. Schriiver are generalized to directed situation. Fur- thermore, two necessary and sufficient conditions for directed linking systems are presented.更多还原