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Chirotopes are a common combinatorial abstraction of (planar) point sets. In this paper we investigate decomposition methods for chirotopes, and their application to the problem of counting the number of triangulations supported by a given…

Computational Geometry · Computer Science 2026-03-12 Mathilde Bouvel , Valentin Féray , Xavier Goaoc , Florent Koechlin

In three-dimensional computational topology, the theory of normal surfaces is a tool of great theoretical and practical significance. Although this theory typically leads to exponential time algorithms, very little is known about how these…

Geometric Topology · Mathematics 2018-10-24 Benjamin A. Burton , João Paixão , Jonathan Spreer

The triangulations of a regular convex polygon are enumerated according to the number of diagonals parallel to a fixed edge. The enumeration uses the Shapiro convolution identity, as well as an interpretation of this identity in terms of…

Combinatorics · Mathematics 2012-08-21 Alon Regev

We study crossing numbers for systoles of congruence surfaces. Taken as a family of curves on a family of surfaces, we show that the growth rate of their intersection is optimally small among all sets of curves of the same cardinality lying…

Geometric Topology · Mathematics 2025-08-29 Claire Burrin , Hugo Parlier

Consider a component of the Hilbert scheme whose general point corresponds to a degree d genus g smooth irreducible and nondegenerate curve in a projective variety X. We give lower bounds for the dimension of such a component when X is P^3,…

Algebraic Geometry · Mathematics 2008-08-28 Dawei Chen

Suppose an orientation preserving action of a finite group $G$ on the closed surface $\Sigma_g$ of genus $g>1$ extends over the 3-torus $T^3$ for some embedding $\Sigma_g\subset T^3$. Then $|G|\le 12(g-1)$, and this upper bound $12(g-1)$…

Geometric Topology · Mathematics 2016-03-29 Sheng Bai , Vanessa Robins , Chao Wang , Shicheng Wang

This work is motivated by two problems: 1) The approach of manifolds and spaces by triangulations. 2) The complexity growth in sequences of polyhedra. Considering both problems as related, new criteria and methods for approximating smooth…

Differential Geometry · Mathematics 2012-05-22 Daniel J. Pons

This paper is about the geometry of flip-graphs associated to triangulations of surfaces. More precisely, we consider a topological surface with a privileged boundary curve and study the spaces of its triangulations with n vertices on the…

Geometric Topology · Mathematics 2017-08-22 Hugo Parlier , Lionel Pournin

This paper studies binary quadratic programs in which the objective is defined by a Euclidean distance matrix, subject to a general polyhedral constraint set. This class of nonconcave maximisation problems includes the capacitated,…

Optimization and Control · Mathematics 2023-09-19 Hoa T. Bui , Sandy Spiers , Ryan Loxton

The aim of this paper is to study symmetries of linearly singular differential equations, namely, equations that can not be written in normal form because the derivatives are multiplied by a singular linear operator. The concept of…

Mathematical Physics · Physics 2009-11-07 Xavier Gracia , Josep M. Pons

This article is devoted to the study of mappings defined in the region on the plane. Under certain conditions, the upper estimate of the distortion of the modulus of families of paths is obtained. Similarly, the upper estimate of the…

Complex Variables · Mathematics 2022-07-22 E. Sevost'yanov , V. Targonskii

We study generalization of median triangles on the plane with two complex parameters. By specialization of the parameters, we produce periodical motion of a triangle whose vertices trace each other on a common closed orbit.

Metric Geometry · Mathematics 2020-09-15 Hiroaki Nakamura , Hiroyuki Ogawa

A metric polygon is a metric space comprised of a finite number of closed intervals joined cyclically. The second-named author and Ntalampekos recently found a method to bi-Lipschitz embed an arbitrary metric triangle in the Euclidean plane…

Metric Geometry · Mathematics 2025-11-06 Xinyuan Luo , Matthew Romney , Alexandria L. Tao

Counting Euclidean triangulations with vertices in a finite set $\C$ of the convex hull $\conv(\C)$ of $\C$ is difficult in general, both algorithmically and theoretically. The aim of this paper is to describe nearly convex polygons, a…

Combinatorics · Mathematics 2010-12-13 Roland Bacher , Frédéric Mouton

We study surfaces with one constant principal curvature in Riemannian and Lorentzian three-dimensional space forms. Away from umbilic points they are characterized as one-parameter foliations by curves of constant curvature, each of these…

Differential Geometry · Mathematics 2014-02-21 Henri Anciaux

We study the moduli space of euclidean structures with cone points on a surface, and describe a decomposition into cells each of which corresponds to a given combinatorial type of Delaunay tessellation. We use some of the ideas to study…

Geometric Topology · Mathematics 2007-05-23 Igor Rivin

In this paper, we present several new bounds for the norm and numerical radius of sums of Hilbert space operators. The obtained bounds form a new collection that enriches our understanding of these bounds. We compare our bounds with the…

Functional Analysis · Mathematics 2026-02-17 Zameddin I. Ismailov , Pembe Ipek Al , Hamid Reza Moradi , Mohammad Sababheh

We give several examples of tilting-discrete symmetric algebras; in particular, one explores which algebra has tilting-discrete trivial extension. We provide a counter example of the conjecture stating any {\tau} -tilting finite symmetric…

Representation Theory · Mathematics 2025-11-11 Takuma Aihara

In this work we study line arrangements consisting in lines passing through three non-aligned points. We call them triangular arrangements. We prove that any combinatorics of a triangular arrangement is always realized by a…

Algebraic Geometry · Mathematics 2026-04-15 Simone Marchesi , Jean Vallès

We prove that if a complete Riemannian surface $(\Sigma,d_\Sigma)$ is quasi-isometric to some bounded degree graph $G$, then $\Sigma$ admits a triangulation whose 1-skeleton is quasi-isometric to it when equipped with the simplicial metric.…

Metric Geometry · Mathematics 2026-05-19 Agelos Georgakopoulos , Federico Vigolo