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We initiate the study of subpolytopes of the permutahedron that arise as the convex hulls of stack-sorting on permutations. We primarily focus on $Ln1$ permutations, i.e., permutations of length $n$ whose penultimate and last entries are…

Combinatorics · Mathematics 2025-02-11 Eon Lee , Carson Mitchell , Andrés R. Vindas-Meléndez

Let $\Delta$ be an $n$-dimensional lattice polytope. The smallest non-negative integer $i$ such that $k \Delta$ contains no interior lattice points for $1 \leq k \leq n - i$ we call the degree of $\Delta$. We consider lattice polytopes of…

Combinatorics · Mathematics 2011-11-09 Victor Batyrev , Benjamin Nill

A theorem of Scott gives an upper bound for the normalized volume of lattice polygons with exactly $i>0$ interior lattice points. We will show that the same bound is true for the normalized volume of lattice polytopes of degree 2 even in…

Combinatorics · Mathematics 2009-01-13 Jaron Treutlein

Given a set $S \subseteq \mathbb{R}^d$, a hollow polytope has vertices in $S$ but contains no other point of $S$ in its interior. We prove upper and lower bounds on the maximum number of vertices of hollow polytopes whose facets are…

Metric Geometry · Mathematics 2025-04-25 Srinivas Arun , Travis Dillon

A well known result by Lagarias and Ziegler states that there are finitely many equivalence classes of d-dimensional lattice polytopes having volume at most K, for fixed constants d and K. We describe an algorithm for the complete…

Combinatorics · Mathematics 2018-11-09 Gabriele Balletti

Considering $n\times n\times n$ stochastic tensors $(a_{ijk})$ (i.e., nonnegative hypermatrices in which every sum over one index $i$, $j$, or $k$, is 1), we study the polytope ($\Omega_{n}$) of all these tensors, the convex set ($L_n$) of…

Combinatorics · Mathematics 2016-09-14 Haixia Chang , Vehbi E. Paksoy , Fuzhen Zhang

We prove that, for fixed n there exist only finitely many embeddings of Q-factorial toric varieties X into P^n that are induced by a complete linear system. The proof is based on a combinatorial result that for fixed nonnegative integers d…

We give an explicit upper bound on the volume of lattice simplices with fixed positive number of interior lattice points. The bound differs from the conjectural sharp upper bound only by a linear factor in the dimension. This improves…

Combinatorics · Mathematics 2017-10-25 Gennadiy Averkov , Jan Krümpelmann , Benjamin Nill

In this short note we give a construction of an infinite series of Delone simplices whose relative volume grows super-exponentially with their dimension. This dramatically improves the previous best lower bound, which was linear.

Combinatorics · Mathematics 2007-05-23 F. Santos , A. Schuermann , F. Vallentin

In this paper, we consider integral maximal lattice-free simplices. Such simplices have integer vertices and contain integer points in the relative interior of each of their facets, but no integer point is allowed in the full interior. In…

Optimization and Control · Mathematics 2009-05-19 Kent Andersen , Christian Wagner , Robert Weismantel

Recent progress on flow polytopes indicates many interesting families with product formulas for their volume. These product formulas are all proved using analytic techniques. Our work breaks from this pattern. We define a family of closely…

Combinatorics · Mathematics 2017-07-12 Karola Mészáros , Connor Simpson , Zoe Wellner

After giving a short introduction on smooth lattice polytopes, I will present a proof for the finiteness of smooth lattice polytopes with few lattice points. The argument is then turned into an algorithm for the classification of smooth…

Combinatorics · Mathematics 2010-01-05 Benjamin Lorenz

Kalai proved that the simplicial polytopes with g_2=0 are the stacked polytopes. We characterize the g_2=1 case. Specifically, we prove that every simplicial d-polytope (d>=4) which is prime and with g_2=1 is combinatorially equivalent…

Combinatorics · Mathematics 2009-12-10 Eran Nevo , Eyal Novinsky

In the frame of a classification of general square systems of polynomial equations solvable by radicals, Esterov and Gusev succeeded in classifying all spanning lattice polytopes whose normalized volumes are at most $4$. In the present…

Combinatorics · Mathematics 2020-09-08 Takayuki Hibi , Akiyoshi Tsuchiya

Consider the Birkhoff polytope of n by n doubly-stochastic matrices. As the Birkhoff-von Neumann theorem famously states, its vertex set coincides with the set of all n by n permutation matrices. Here we seek a higher-dimensional analog of…

Combinatorics · Mathematics 2012-08-22 Nathan Linial , Zur Luria

We introduce a sorting machine consisting of $k+1$ stacks in series: the first $k$ stacks can only contain elements in decreasing order from top to bottom, while the last one has the opposite restriction. This device generalizes \cite{SM},…

Data Structures and Algorithms · Computer Science 2019-10-10 Giulio Cerbai , Lapo Cioni , Luca Ferrari

If $P$ is a lattice polytope (that is, the convex hull of a finite set of lattice points in $\mathbf{R}^n$), then every sum of $h$ lattice points in $P$ is a lattice point in the $h$-fold sumset $hP$. However, a lattice point in the…

Number Theory · Mathematics 2020-04-17 Melvyn B. Nathanson

A stacking operation adds a $d$-simplex on top of a facet of a simplicial $d$-polytope while maintaining the convexity of the polytope. A stacked $d$-polytope is a polytope that is obtained from a $d$-simplex and a series of stacking…

Computational Geometry · Computer Science 2017-03-03 Erik D. Demaine , Andre Schulz

We classify lattice $3$-polytopes of width larger than one and with exactly $6$ lattice points. We show that there are $74$ polytopes of width $2$, two polytopes of width $3$, and none of larger width. We give explicit coordinates for…

Combinatorics · Mathematics 2016-05-12 Mónica Blanco , Francisco Santos

We show that up to unimodular equivalence there are only finitely many d-dimensional lattice polytopes without interior lattice points that do not admit a lattice projection onto a (d-1)-dimensional lattice polytope without interior lattice…

Combinatorics · Mathematics 2011-04-26 Benjamin Nill , Günter M. Ziegler
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