中文

正规循环多面体与非非常丰沛的循环多面体

组合数学 2019-02-20 v4

摘要

ddnn为正整数,满足nd+1n \geq d + 1,且τ1,...,τn\tau_{1}, ..., \tau_{n}为整数,满足τ1<...<τn\tau_{1} < ... < \tau_{n}。令Cd(τ1,...,τn)\RRdC_{d}(\tau_{1}, ..., \tau_{n}) \subset \RR^{d}表示维度为dd、具有nn个顶点(τ1,τ12,...,τ1d),...,(τn,τn2,...,τnd)(\tau_{1},\tau_{1}^{2},...,\tau_{1}^{d}), ..., (\tau_{n},\tau_{n}^{2},...,\tau_{n}^{d})的循环多面体。我们感兴趣的是找到最小整数γd\gamma_{d},使得若对于1i<n1 \leq i < nτi+1τiγd\tau_{i+1} - \tau_{i} \geq \gamma_{d},则Cd(τ1,...,τn)C_{d}(\tau_{1}, ..., \tau_{n})是正规的。已知结果之一是γdd(d+1)\gamma_{d} \leq d (d + 1)。本文证明了新的不等式γdd21\gamma_{d} \leq d^{2} - 1。此外,还证明了若d4d \geq 4τ3τ2=1\tau_{3} - \tau_{2} = 1,则Cd(τ1,...,τn)C_{d}(\tau_{1}, ..., \tau_{n})不是非常丰沛的。

关键词

引用

@article{arxiv.1202.6117,
  title  = {Normal cyclic polytopes and cyclic polytopes that are not very ample},
  author = {Takayuki Hibi and Akihiro Higashitani and Lukas Katthän and Ryota Okazaki},
  journal= {arXiv preprint arXiv:1202.6117},
  year   = {2019}
}

备注

17 pages