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We investigate deformations of a skew group algebra that arise from a finite group acting on a polynomial ring. When the characteristic of the underlying field divides the order of the group, a new type of deformation emerges that does not…

Rings and Algebras · Mathematics 2013-12-13 Anne V. Shepler , Sarah Witherspoon

Symmetric edge polytopes of graphs and root polytopes of semi-balanced digraphs are two classes of lattice polytopes whose $h^*$-polynomials have interesting properties and generalize important graph polynomials. For both classes of…

Combinatorics · Mathematics 2024-08-16 Tamás Kálmán , Lilla Tóthmérész

We show there is an uncountable number of parallel total perfect codes in the integer lattice graph ${\Lambda}$ of $\R^2$. In contrast, there is just one 1-perfect code in ${\Lambda}$ and one total perfect code in ${\Lambda}$ restricting to…

Combinatorics · Mathematics 2015-03-13 Italo J. Dejter

An interesting open problem in Ehrhart theory is to classify those lattice polytopes having a unimodal $h^*$-vector. Although various sufficient conditions have been found, necessary conditions remain a challenge. In this paper, we consider…

Combinatorics · Mathematics 2014-08-28 Benjamin Braun , Robert Davis

It is shown that, under mild conditions, a complex reflection group $G(r,p,n)$ may be decomposed into a set-wise direct product of cyclic subgroups. This property is then used to extend the notion of major index and a corresponding Hilbert…

Combinatorics · Mathematics 2007-08-14 Robert Shwartz , Ron M. Adin , Yuval Roichman

Cycle polytopes of matroids have been introduced in combinatorial optimization as a generalization of important classes of polyhedral objects like cut polytopes and Eulerian subgraph polytopes associated to graphs. Here we start an…

Combinatorics · Mathematics 2021-05-04 Tim Römer , Sara Saeedi Madani

Zonotopes are a rich and fascinating family of polytopes, with connections to many areas of mathematics. In this article we provide a brief survey of classical and recent results related to lattice zonotopes. Our emphasis is on connections…

Combinatorics · Mathematics 2018-08-17 Benjamin Braun , Andrés R. Vindas-Meléndez

It is known that polytopes with at most two nonsimple vertices are reconstructible from their graphs, and that $d$-polytopes with at most $d-2$ nonsimple vertices are reconstructible from their 2-skeletons. Here we close the gap between 2…

Combinatorics · Mathematics 2018-11-28 Guillermo Pineda-Villavicencio , Julien Ugon , David Yost

We investigate the reflexivity of the isometry group and the automorphism group of some important metric linear spaces and algebras. The paper consists of the following sections: 1. Preliminaries. 2. Sequence spaces. 3. Spaces of measurable…

Functional Analysis · Mathematics 2007-05-23 Felix Cabello Sanchez , Lajos Molnar

The {\em perfect matching complex} of a graph is the simplicial complex on the edge set of the graph with facets corresponding to perfect matchings of the graph. This paper studies the perfect matching complexes, $\mathcal{M}_p(H_{k \times…

Combinatorics · Mathematics 2022-09-08 Margaret Bayer , Marija Jelić Milutinović , Julianne Vega

We completely classify the locally finite, infinite graphs with pure mapping class groups admitting a coarsely bounded generating set. We also study algebraic properties of the pure mapping class group: We establish a semidirect product…

Group Theory · Mathematics 2025-08-06 George Domat , Hannah Hoganson , Sanghoon Kwak

We study a family of the Laurent biorthogonal polynomials arising from the Hermite continued fraction for a ratio of two complete elliptic integrals. Recurrence coefficients, explicit expression and the weight function for these polynomials…

Classical Analysis and ODEs · Mathematics 2008-04-24 Luc Vinet , Alexei Zhedanov

We study well-rounded ideal lattices from totally definite quaternion algebras. We prove existence and classification results, and illustrate our methods with examples.

Rings and Algebras · Mathematics 2025-12-04 Yuan Xiang Chew , Frédérique Oggier

In 2012 Gubeladze (Adv.\ Math.\ 2012) introduced the notion of k-convex-normal polytopes to show that integral polytopes all of whose edges are longer than 4d(d+1) have the integer decomposition property. In the first part of this paper we…

Combinatorics · Mathematics 2014-10-24 Christian Haase , Jan Hofmann

We provide a characterization of the compressed lattice polytopes in terms of their facet defining inequalities and we show that every compressed lattice polytope is affinely isomorphic to a 0/1-polytope. As an application, we characterize…

Combinatorics · Mathematics 2007-06-13 Seth Sullivant

Let $G$ be a finite group. A number of graphs with the vertex set $G$ have been studied, including the power graph, enhanced power graph, and commuting graph. These graphs form a hierarchy under the inclusion of edge sets, and it is useful…

Combinatorics · Mathematics 2021-12-07 G. Arunkumar , Peter J. Cameron , Rajat Kanti Nath , Lavanya Selvaganesh

Leavitt path algebras are free algebras subject to relations induced by directed graphs. This paper investigates the ideals of Leavitt path algebras, with an emphasis on the relationship between graph-theoretic properties of a directed…

Rings and Algebras · Mathematics 2025-10-09 Yvan Grinspan , Seth Yoo

We construct infinite families of abstract regular polytopes of type $\{4,p_1,\ldots,p_{n-1}\}$ from extensions of centrally symmetric spherical abstract regular $n$-polytopes. In addition, by applying the halving operation, we obtain…

Combinatorics · Mathematics 2021-04-01 Claudio Alexandre Piedade

In this work, we define an orthogonal graph on the set of equivalence classes of $(2\nu + \delta)-$tuples over $\mathbb{Z}_{2^n}$ where $n$ and $\nu$ are positive integers and $\delta = 0, 1$ or $2$. We classify our graph if it is strongly…

Combinatorics · Mathematics 2019-01-07 Songpon Sriwongsa

The Birkhoff polytope, defined to be the convex hull of $n\times n$ permutation matrices, is a well studied polytope in the context of the Ehrhart theory. This polytope is known to have many desirable properties, such as the Gorenstein…

Combinatorics · Mathematics 2019-06-06 Florian Kohl , McCabe Olsen
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