arXivDaily arXiv每日学术速递 周一至周五更新
北美退伍军人节(Veterans Day),12 日无更新
arXiv 1207.0164math.CO
收藏

凸集自由和的格点generating functions

Lattice-point generating functions for free sums of convex sets

Matthias Beck, Pallavi Jayawant, Tyrrell B. McAllister

摘要:

令$\J$和$\K$是$\R^{n}$中的凸集,其仿射跨度相交于$\J \cap \K$中的单个有理点,并令$\J \oplus \K = \conv(\J \cup \K)$。给出了生成函数{equation*} σ_{ \cone(\J \oplus \K)}(z_1,...,z_n,z_{n+1})= \sum_{(m_1,..., m_n) \in t(\J \oplus \K) \cap \Z^{n}} z_1^{m_1}. z_n^{m_n} z_{n+1} ^{t} {方程 *},在$\J$和$\K$上的各种条件下,根据$σ_{\cone \J}$和$σ_{\cone \K}$,在$\J \oplus \K$的所有整数膨胀中的格点。本文的工作是由B的一个乘积公式激发的(并恢复了它)。Braun的Ehrhart系列的$¶\oplus \Q$的情况下,$¶$和$\Q$是晶格多面体包含的起源,其中之一是自反的。特别是,我们找到了Braun公式及其多元类似物的充分必要条件。

英文摘要:

Let $\J$ and $\K$ be convex sets in $\R^{n}$ whose affine spans intersect at a single rational point in $\J \cap \K$, and let $\J \oplus \K = \conv(\J \cup \K)$. We give formulas for the generating function {equation*} σ_{\cone(\J \oplus \K)}(z_1,..., z_n, z_{n+1}) = \sum_{(m_1,..., m_n) \in t(\J \oplus \K) \cap \Z^{n}} z_1^{m_1}... z_n^{m_n} z_{n+1}^{t} {equation*} of lattice points in all integer dilates of $\J \oplus \K$ in terms of $σ_{\cone \J}$ and $σ_{\cone \K}$, under various conditions on $\J$ and $\K$. This work is motivated by (and recovers) a product formula of B.\ Braun for the Ehrhart series of $¶\oplus \Q$ in the case where $¶$ and $\Q$ are lattice polytopes containing the origin, one of which is reflexive. In particular, we find necessary and sufficient conditions for Braun's formula and its multivariate analogue.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑