Locally anti-blocking $\mathbf{g}$-polytopes for flow polytopes
流多面体的局部反阻塞 $\mathbf{g}$-多面体
Jonah Berggren, Benjamin Braun, Alvaro Cornejo, James Ford McElroy, Chloe' Napier, Zachery Peterson, Williem Rizer, Khrystyna Serhiyenko, Martha Yip
AI总结 本文研究有向无环图流多面体的局部反阻塞 $\mathbf{g}$-多面体,给出了组合刻画、最小面特征、DKK三角剖分的拉回三角剖分性质,并引入相干图模型。
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给定一个无环有向图(DAG),强度为1的流空间是一个格点多面体,称为该DAG的流多面体。如果该DAG具有充足框架,则流多面体是Gorenstein的,并且它线性投影到一个称为$\mathbf{g}$-多面体的自反多面体上。我们给出了具有局部反阻塞$\mathbf{g}$-多面体的充足框架DAG的组合刻画,并刻画了包含固定一对顶点的$\mathbf{g}$-多面体的最小面。我们证明在这种情况下,由流多面体的DKK三角剖分诱导的$\mathbf{g}$-多面体的单形剖分是一个拉回三角剖分,并刻画了产生DKK三角剖分的拉回顺序。为了证明我们的结果,我们引入并研究了相干图,这是具有局部反阻塞$\mathbf{g}$-多面体的充足框架DAG的相干性的组合模型。最后,我们指出了这些结果在温和中山代数$\mathbf{g}$-多面体设置中的可能推广。
Given an acyclic directed graph (DAG), the space of strength one flows is a lattice polytope called the flow polytope of the DAG. If the DAG admits an ample framing, then the flow polytope is Gorenstein and it linearly projects onto a reflexive polytope called the $\mathbf{g}$-polytope. We provide a combinatorial characterization of amply framed DAGs that have a locally anti-blocking $\mathbf{g}$-polytope, and we characterize the minimal faces of the $\mathbf{g}$-polytope containing a fixed pair of vertices. We prove in this case that the unimodular triangulation of the $\mathbf{g}$-polytope induced by the DKK triangulation of the flow polytope is a pulling triangulation, and we characterize the pulling orders that yield the DKK triangulation. To prove our results, we introduce and study coherence diagrams, a combinatorial model of coherence for amply framed DAGs with locally anti-blocking $\mathbf{g}$-polytopes. We conclude by indicating possible extensions of these results to the setting of $\mathbf{g}$-polytopes for gentle Nakayama algebras.