论文标题

计数比赛得分序列

Counting tournament score sequences

论文作者

Claesson, Anders, Dukes, Mark, Franklín, Atli Fannar, Stefánsson, Sigurður Örn

论文摘要

比赛的得分顺序是其以非续顺序排列的顶点的序列。计数与$ N $顶点的比赛的分数序列的问题超过100年(Macmahon 1920)。 2013年,汉娜(Hanna)猜想了这些数字令人惊讶且优雅的递归。我们通过证明它是我们的主要定理的推论,在肯定中解决了这一猜想,这是用划分索引的得分序列生成函数的分解。我们还得出了用于计数得分序列的封闭公式和二次时间算法。

The score sequence of a tournament is the sequence of the out-degrees of its vertices arranged in nondecreasing order. The problem of counting score sequences of a tournament with $n$ vertices is more than 100 years old (MacMahon 1920). In 2013 Hanna conjectured a surprising and elegant recursion for these numbers. We settle this conjecture in the affirmative by showing that it is a corollary to our main theorem, which is a factorization of the generating function for score sequences with a distinguished index. We also derive a closed formula and a quadratic time algorithm for counting score sequences.

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