论文标题
限制性甲骨文下的矩阵交叉点
Matroid Intersection under Restricted Oracles
论文作者
论文摘要
Matroid交点是Matroid理论最强大的框架之一,它概括了组合优化中的各种问题。埃德蒙兹(Edmonds)的基本定理为未加权的设置提供了最小的最大特征,而弗兰克(Frank)的重量分类定理为加权案例提供了一种。为这些问题开发了几种有效的算法,所有算法都依赖于两个矩阵的常规甲壳的使用。 在本文中,我们考虑了限制性甲状管下的矩阵交叉问题的障碍性。特别是,我们专注于等级总和,共同的独立性和最大排名oracles。我们给出了在等级总和ORACLE下加权矩阵交叉点的强烈多项式时间算法。在常见的独立性甲骨文模型中,我们证明,当一个矩形是一个分区矩阵时,未加权的矩形相交问题是可以解决的,而当一个矩形是基本分裂的矩阵时,即使是加权的情况也可以解决。最后,我们表明,共同的独立性和最高排名座共同足够强大,足以实现我们的算法的步骤。
Matroid intersection is one of the most powerful frameworks of matroid theory that generalizes various problems in combinatorial optimization. Edmonds' fundamental theorem provides a min-max characterization for the unweighted setting, while Frank's weight-splitting theorem provides one for the weighted case. Several efficient algorithms were developed for these problems, all relying on the usage of one of the conventional oracles for both matroids. In the present paper, we consider the tractability of the matroid intersection problem under restricted oracles. In particular, we focus on the rank sum, common independence, and maximum rank oracles. We give a strongly polynomial-time algorithm for weighted matroid intersection under the rank sum oracle. In the common independence oracle model, we prove that the unweighted matroid intersection problem is tractable when one of the matroids is a partition matroid, and that even the weighted case is solvable when one of the matroids is an elementary split matroid. Finally, we show that the common independence and maximum rank oracles together are strong enough to realize the steps of our algorithm under the rank sum oracle.