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We study generating functions of strict and non-strict order polynomials of series-parallel posets, called order series. These order series are closely related to Ehrhart series and h*-polynomials of the associated order polytopes. We…

Combinatorics · Mathematics 2026-01-27 Jose Antonio Arciniega-Nevarez , Marko Berghoff , Eric Dolores-Cuenca

We consider the problem of sampling from the uniform distribution on the set of Eulerian orientations of subgraphs of the triangular lattice. Although it is known that this can be achieved in polynomial time for any graph, the algorithm…

Discrete Mathematics · Computer Science 2007-05-23 Paidi Creed

To work at scale, a complete image indexing system comprises two components: An inverted file index to restrict the actual search to only a subset that should contain most of the items relevant to the query; An approximate distance…

Computer Vision and Pattern Recognition · Computer Science 2017-12-14 Himalaya Jain , Joaquin Zepeda , Patrick Pérez , Rémi Gribonval

For each permutation $w$, we consider the set $\mathrm{PD}(w)$ of reduced pipe dreams for $w$, partially ordered so that cover relations correspond to (generalized) chute moves. Settling a conjecture of Rubey from 2012, we prove that…

Combinatorics · Mathematics 2025-07-18 Ilani Axelrod-Freed , Colin Defant , Hanna Mularczyk , Son Nguyen , Katherine Tung

Many approximation algorithms and heuristic algorithms to find a fair clustering have emerged. In this paper we define a new and natural variant of fair clustering problem and design a polynomial time algorithm to compute an optimal fair…

Computational Geometry · Computer Science 2025-11-12 Ayano Moritaka , Shin-ichi Nakano , Kento Tanaka , Noriaki Yoshida

Given a rational pointed $n$-dimensional cone $C$, we study the integer Carath\'{e}odory rank $\operatorname{CR}(C)$ and its asymptotic form $\operatorname{CR^{\rm a}}(C)$, where we consider ``most'' integer vectors in the cone. The main…

Combinatorics · Mathematics 2023-03-27 Iskander Aliev , Martin Henk , Mark Hogan , Stefan Kuhlmann , Timm Oertel

This paper studies the poset of eigenspaces of elements of an imprimitive unitary reflection group, for a fixed eigenvalue, ordered by the reverse of inclusion. The study of this poset is suggested by the eigenspace theory of Springer and…

Combinatorics · Mathematics 2013-04-03 Justin Koonin

The combinatorial theory for the set of parity alternating permutations is expounded. In view of the numbers of ascents and inversions, several enumerative aspects of the set are investigated. In particular, it is shown that signed Eulerian…

Combinatorics · Mathematics 2017-06-13 Shinji Tanimoto

Huggett and Moffatt characterized all bipartite partial duals of a plane graph in terms of all-crossing directions of its medial graph. Then Metsidik and Jin characterized all Eulerian partial duals of a plane graph in terms of…

Combinatorics · Mathematics 2017-06-14 Qingying Deng , Xian'an Jin

In this paper, we study the dualization in distributive lattices, a generalization of the well-known hypergraph dualization problem. We in particular propose equivalent formulations of the problem in terms of graphs, hypergraphs, and…

Discrete Mathematics · Computer Science 2020-05-26 Oscar Defrain , Lhouari Nourine , Takeaki Uno

We consider a family of structural descriptors for visual data, namely covariance descriptors (CovDs) that lie on a non-linear symmetric positive definite (SPD) manifold, a special type of Riemannian manifolds. We propose an improved…

Computer Vision and Pattern Recognition · Computer Science 2019-09-27 Kai-Xuan Chen , Xiao-Jun Wu , Jie-Yi Ren , Rui Wang , Josef Kittler

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

The security of code-based cryptography relies primarily on the hardness of generic decoding with linear codes. The best generic decoding algorithms are all improvements of an old algorithm due to Prange: they are known under the name of…

Cryptography and Security · Computer Science 2017-02-09 Thomas Debris-Alazard , Jean-Pierre Tillich

The clustered planarity problem (c-planarity) asks whether a hierarchically clustered graph admits a planar drawing such that the clusters can be nicely represented by regions. We introduce the cd-tree data structure and give a new…

Data Structures and Algorithms · Computer Science 2015-06-19 Thomas Bläsius , Ignaz Rutter

In a recent study by Tenner, the concept of the interval poset of a permutation was introduced to effectively represent all intervals and their inclusions within a permutation. In this paper, we present a new geometric viewpoint on interval…

Combinatorics · Mathematics 2025-09-30 Eli Bagno , Estrella Eisenberg , Shulamit Reches , Moriha Sigron

The partition problem is a well-known basic NP-complete problem. We mainly consider the optimization version of it in this paper. The problem has been investigated from various perspectives for a long time and can be solved efficiently in…

Discrete Mathematics · Computer Science 2024-05-10 Susumu Kubo

In this note we construct a poset map from a Boolean algebra to the Bruhat order which unveils an interesting connection between subword complexes, sorting orders, and certain totally nonnegative spaces. This relationship gives a new proof…

Combinatorics · Mathematics 2010-11-05 Drew Armstrong , Patricia Hersh

We introduce Lehmer codes, with immersions in the Bruhat order, for several finite Coxeter groups, including all the classical Weyl groups. This allows to associate to each lower Bruhat interval of these groups a multicomplex whose…

Combinatorics · Mathematics 2025-09-09 Davide Bolognini , Paolo Sentinelli

A tetrahedron is the simplest shape that cannot be rotated into its mirror image in 3D. The 4-Point Correlation Function (4PCF), which quantifies excess clustering of quartets of galaxies over random, is the lowest-order statistic sensitive…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-27 Jiamin Hou , Zachary Slepian , Robert N. Cahn

We prove a simple formula for arbitrary cluster variables in the marked surfaces model. As part of the formula, we associate a labeled poset to each tagged arc, such that the associated $F$-polynomial is a weighted sum of order ideals. Each…

Combinatorics · Mathematics 2024-04-19 Vincent Pilaud , Nathan Reading , Sibylle Schroll