发表机构
Georgia State University(佐治亚州立大学)
机构由 AI 辅助整理,请以论文原文为准。AI 中文总结
本文证明了拉丁方和斯坦纳三元系中近生成匹配的精确计数结果,给出了指数级数量的部分横截和匹配,证实了相关猜想和预测。
AI 中文摘要
Montgomery 最近证明,对于足够大的 $n$,每个 $n$ 阶拉丁方都有一个包含 $n-1$ 个单元格的部分横截,并且每个 $n$ 阶斯坦纳三元系都有一个包含 $\lfloor n/3\rfloor-1$ 条边的匹配,从而证实了 Ryser--Brualdi--Stein 猜想在偶数 $n$ 情形下的正确性以及 Brouwer 的猜想。我们证明了这些结果的尖锐计数细化:存在一个绝对常数 $c>0$,使得对于足够大的 $n$,1) 每个 $n$ 阶拉丁方都有 $\left((1\pm n^{-c})\frac{n}{\mathrm {e}^2}\right)^n$ 个包含 $n-1$ 个单元格的部分横截;2) 每个 $n$ 阶斯坦纳三元系都有 $\left((1\pm n^{-c})\frac{n}{2\mathrm {e}^2}\right)^{\lfloor n/3\rfloor}$ 个包含 $\lfloor n/3\rfloor-1$ 条边的匹配。第一个估计证实了 Montgomery 和 Kelly 的预测。
英文摘要
Montgomery recently proved that for sufficiently large $n$, every Latin square of order $n$ has a partial transversal with $n-1$ cells, and every Steiner triple system of order $n$ has a matching with $\lfloor n/3\rfloor-1$ edges, thus confirming the Ryser--Brualdi--Stein conjecture for even $n$ and the conjecture of Brouwer. We prove sharp enumerative refinements of these results: there is an absolute constant $c>0$ such that, for sufficiently large $n$, 1) every Latin square of order $n$ has $ \left((1\pm n^{-c})\frac{n}{\mathrm {e}^2}\right)^n$ partial transversals with $n-1$ cells; 2) every Steiner triple system of order $n$ has $ \left((1\pm n^{-c})\frac{n}{2\mathrm {e}^2}\right)^{\lfloor n/3\rfloor}$ matchings with $\lfloor n/3\rfloor-1$ edges. The first estimate confirms predictions of Montgomery and Kelly.
Comments18 pages