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We give a structure theorem for n-dimensional smooth toric Fano varieties whose associated polytope has "many" pairs of centrally symmetric vertices.

Algebraic Geometry · Mathematics 2007-05-23 Cinzia Casagrande

We give an approximate algorithm of computing holonomic systems of linear differential equations for definite integrals with parameters. We show that this algorithm gives a correct answer in finite steps, but we have no general stopping…

Symbolic Computation · Computer Science 2010-12-27 Hiromasa Nakayama , Nobuki Takayama

Let X be a complex, Gorenstein, Q-factorial, toric Fano variety. We prove two conjectures on the maximal Picard number of X in terms of its dimension and its pseudo-index, and characterize the boundary cases. Equivalently, we determine the…

Algebraic Geometry · Mathematics 2007-05-23 C. Casagrande

Symmetric edge polytopes are a class of lattice polytopes constructed from finite simple graphs. In the present paper we highlight their connections to the Kuramoto synchronization model in physics -- where they are called adjacency…

Combinatorics · Mathematics 2022-09-02 Alessio D'Alì , Emanuele Delucchi , Mateusz Michałek

Directed graphs can be studied by their associated directed flag complex. The homology of this complex has been successful in applications as a topological invariant for digraphs. Through comparison with path homology theory, we derive a…

Algebraic Topology · Mathematics 2024-11-08 Thomas Chaplin , Heather A. Harrington , Ulrike Tillmann

We investigate symmetric edge polytopes generated by Erd\H{o}s--R\'enyi random graphs in a high-dimensional regime. These objects provide a natural and largely unexplored model of random lattice polytopes, in which geometric properties are…

Combinatorics · Mathematics 2026-03-12 Torben Donzelmann , Martina Juhnke , Benedikt Rednoß , Christoph Thäle

The symmetric projective varieties of rank one are all smooth and Fano by a classic result of Akhiezer. We classify the locally factorial (respectively smooth) projective symmetric $G$-varieties of rank 2 which are Fano. When $G$ is…

Algebraic Geometry · Mathematics 2010-12-22 Alessandro Ruzzi

We develop a homotopy theory of directed graphs based on cubical homotopy groups, also referred to as A-groups or reduced GLMY homotopy groups. Localizing the category of directed graphs at morphisms that induce isomorphisms on these groups…

Algebraic Topology · Mathematics 2026-05-07 Briony Eldridge , Sergei O. Ivanov , Xiaomeng Xu , Shing-Tung Yau , Mengmeng Zhang

We study cosmological polytopes induced by Erd\H{o}s--R\'enyi random graphs in a high-dimensional regime. These graph-based lattice polytopes form a natural model of random lattice polytopes in which geometric features are determined by the…

Combinatorics · Mathematics 2026-05-25 Torben Donzelmann , Martina Juhnke , Benedikt Rednoß , Christoph Thäle

It is known that every lattice polytope is unimodularly equivalent to a face of some reflexive polytope. A stronger question is to ask whether every $(0,1)$-polytope is unimodularly equivalent to a facet of some reflexive polytope. A large…

Combinatorics · Mathematics 2020-09-08 Takahiro Nagaoka , Akiyoshi Tsuchiya

Monotone polytopes, also known as smooth reflexive polytopes, are the polytopes associated to monotone symplectic toric manifolds and Gorenstein Fano toric varieties. We first show that the only monotone polytopes admitting blow-ups at…

Symplectic Geometry · Mathematics 2026-03-20 Álvaro Pelayo , Francisco Santos

We show that if a Fano manifold has discrete automorphism group and admits a polarized K\"ahler-Einstein metric, then there exists a sequence of anticanonically balanced metrics converging smoothly to the K\"ahler-Einstein metric. Our proof…

Differential Geometry · Mathematics 2022-04-27 Louis Ioos

Smooth Fano polytopes (SFP) play an important role in toric geometry and combinatorics. In this paper, we introduce a specific subcollection of them, i.e., the unimodular smooth Fano polytopes (USFP). In Section 2, they are verified to…

Combinatorics · Mathematics 2024-10-01 Binnan Tu

The symmetric edge polytopes of odd cycles (del Pezzo polytopes) are known as smooth Fano polytopes. In this paper, we show that if the length of the cycle is 127, then the Ehrhart polynomial has a root whose real part is greater than the…

Combinatorics · Mathematics 2019-01-11 Hidefumi Ohsugi , Kazuki Shibata

A roundtrip spanner of a directed graph $G$ is a subgraph of $G$ preserving roundtrip distances approximately for all pairs of vertices. Despite extensive research, there is still a small stretch gap between roundtrip spanners in directed…

Data Structures and Algorithms · Computer Science 2020-05-01 Ruoxu Cen , Ran Duan , Yong Gu

This is the second report of our work on the construction of directed strongly regular graphs. In our previous work, we constructed a couple of infinite families of new directed strongly regular graphs on the sets of antiflags of partial…

Combinatorics · Mathematics 2011-02-09 Oktay Olmez , Sung Y. Song

Given a finite quiver (directed graph) without loops and multiedges, the convex hull of the column vector of the incidence matrix is called the directed edge polytope and is an interesting example of lattice polytopes. In this paper, we…

Combinatorics · Mathematics 2022-03-29 Yasuhide Numata , Yusuke Takahashi , Dai Tamaki

We study the linear extension complexity of stable set polytopes of perfect graphs. We make use of known structural results permitting to decompose perfect graphs into basic perfect graphs by means of two graph operations: 2-join and skew…

Combinatorics · Mathematics 2018-11-20 Hao Hu , Monique Laurent

Symmetric edge polytopes of graphs are important object in Ehrhart theory,and have an application to Kuramoto models. In the present paper, we study the upper and lower bounds for the number of facets of symmetric edge polytopes of…

Combinatorics · Mathematics 2025-05-01 Aki Mori , Kenta Mori , Hidefumi Ohsugi

Symmetric edge polytopes, also called adjacency polytopes, are lattice polytopes determined by simple undirected graphs. We introduce the integer array \(\mathrm{maxf}(n,m)\) giving the maximum number of facets of a symmetric edge polytope…

Combinatorics · Mathematics 2023-07-07 Benjamin Braun , Kaitlin Bruegge