论文标题
部分普遍性
Partial permutohedra
论文作者
论文摘要
部分置换螺旋体是晶格多面体,最近由Heuer和Striker引入和研究。对于正整数$ m $和$ n $,部分permutohedron $ \ mathcal {p}(m,n)$是$ \ {0,1,\ ldots,n \}^m的所有向量的凸壳,其非零条目是不同的。我们研究$ \ Mathcal {p}(m,n)$的面部晶格,音量和ehrhart多项式,我们的方法和结果包括以下内容。对于任何$ m $和$ n $,我们可以在$ \ mathcal {p}(m,n)$的非空面之间进行两次培养,某些$ \ {1,\ dots,m \} $的子集的某些链条,从而确认heuer and Triker的猜想,然后我们可以通过$表达$来获得$的表现,以获得$的表征,以获取$的表征。 $ \ MATHCAL {P}(M,N)$。对于任何$ n \ ge m-1 $的任何$ m $和$ n $,我们使用$ \ nathcal {p}(p}(m,n)$的金字塔细分,以建立用于$ \ nathcal {p}(p}(m,n)$的归一化体积的递归公式,然后我们从中获得本卷的封闭表达式。我们还使用雕刻过程(其中$ \ Mathcal {p}(m,n)$可以通过连续从单纯形或超单行中删除某些作品来获得$ \ Mathcal {p}(m,n)$的ehrhart多项式的闭合表达式,并具有$ m $ $ $ $ $ $ $ $ n \ n \ n \ le 3 $ formanize $ n \ le 3 $ formandiese forminate formanive forships for。 $ \ MATHCAL {P}(M,4)$带有任意$ M $的$,以及$ \ Mathcal {p}(m,n)$的ehrhart多项式,带固定$ M \ le4 $和任意$ n \ ge M-1 $。
Partial permutohedra are lattice polytopes which were recently introduced and studied by Heuer and Striker. For positive integers $m$ and $n$, the partial permutohedron $\mathcal{P}(m,n)$ is the convex hull of all vectors in $\{0,1,\ldots,n\}^m$ whose nonzero entries are distinct. We study the face lattice, volume and Ehrhart polynomial of $\mathcal{P}(m,n)$, and our methods and results include the following. For any $m$ and $n$, we obtain a bijection between the nonempty faces of $\mathcal{P}(m,n)$ and certain chains of subsets of $\{1,\dots,m\}$, thereby confirming a conjecture of Heuer and Striker, and we then use this characterization of faces to obtain a closed expression for the $h$-polynomial of $\mathcal{P}(m,n)$. For any $m$ and $n$ with $n\ge m-1$, we use a pyramidal subdivision of $\mathcal{P}(m,n)$ to establish a recursive formula for the normalized volume of $\mathcal{P}(m,n)$, from which we then obtain closed expressions for this volume. We also use a sculpting process (in which $\mathcal{P}(m,n)$ is reached by successively removing certain pieces from a simplex or hypercube) to obtain closed expressions for the Ehrhart polynomial of $\mathcal{P}(m,n)$ with arbitrary $m$ and fixed $n\le 3$, the normalized volume of $\mathcal{P}(m,4)$ with arbitrary $m$, and the Ehrhart polynomial of $\mathcal{P}(m,n)$ with fixed $m\le4$ and arbitrary $n\ge m-1$.