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A surface embedded in space, in such a way that each point has a neighborhood within which the surface is a terrain, projects to an immersed surface in the plane, the boundary of which is a self-intersecting curve. Under what circumstances…

Computational Geometry · Computer Science 2008-06-11 David Eppstein , Elena Mumford

In this paper, we compute the number of self-intersections of a plane projection of a generic complete intersection curve defined by polynomials with the given support. Moreover, we discuss the tropical counterpart of this problem.

Algebraic Geometry · Mathematics 2020-03-24 Arina Voorhaar

The speed of a class of graphs counts the number of graphs on the vertex set $\lbrace 1,\dots, n\rbrace$ inside the class as a function of $n$. In this paper, we investigate this function for many classes of graphs that naturally arise in…

Combinatorics · Mathematics 2021-01-12 Lisa Sauermann

We study limits of convergent sequences of string graphs, that is, graphs with an intersection representation consisting of curves in the plane. We use these results to study the limiting behavior of a sequence of random string graphs. We…

Combinatorics · Mathematics 2014-03-13 Svante Janson , Andrew J. Uzzell

Feynman integrals that have been evaluated in dimensional regularization can be written in terms of generalized hypergeometric functions. It is well known that properties of these functions are revealed in the framework of intersection…

High Energy Physics - Theory · Physics 2019-12-12 Samuel Abreu , Ruth Britto , Claude Duhr , Einan Gardi , James Matthew

On a closed symplectic surface Sigma of genus two or more, we give a new construction of an extended flux map (a crossed homomorphism from the symplectomorphism group Symp(Sigma) to the cohomology group H^1(Sigma;R) that extends the flux…

Geometric Topology · Mathematics 2009-09-04 Matthew B. Day

Given a set of planar curves (Jordan arcs), each pair of which meets -- either crosses or touches -- exactly once, we establish an upper bound on the number of touchings. We show that such a curve family has $O(t^2n)$ touchings, where $t$…

Combinatorics · Mathematics 2017-06-20 Péter Györgyi , Bálint Hujter , Sándor Kisfaludi-Bak

We study quotients of mapping class groups of punctured spheres by suitable large powers of Dehn twists, showing an analogue of Ivanov's theorem for the automorphisms of the corresponding quotients of curve graphs. Then we use this result…

Group Theory · Mathematics 2025-05-28 Giorgio Mangioni , Alessandro Sisto

For an oriented surface $S$, the singular set of a fold map $f:S\rightarrow \mathbb{R}^2$ is a collection of smooth curves, also known as fold singularities. We construct a sharp lower bound on the number of self-intersections of such fold…

Geometric Topology · Mathematics 2026-05-14 Joshua Drouin , Liam Kahmeyer

In many situations it could be interesting to ascertain whether nonparametric regression curves can be grouped, especially when confronted with a considerable number of curves. The proposed testing procedure allows to determine groups with…

Methodology · Statistics 2021-02-02 Nora M. Villanueva , Marta Sestelo , Celestino Ordóñez , Javier Roca-Pardiñas

We outline a strategy for computing intersection numbers on smooth varieties with torus actions using a residue formula of Bott. As an example, Gromov-Witten numbers of twisted cubic and elliptic quartic curves on some general complete…

alg-geom · Mathematics 2008-02-03 G. Ellingsrud , S. A. Strømme

We obtain the bifurcation of some special curves on generic 1-parameter families of surfaces in the Minkowski 3-space. The curves treated here are the locus of points where the induced pseudo metric is degenerate, the discriminant of the…

Differential Geometry · Mathematics 2022-08-10 Marco Antônio do Couto Fernandes

The goal of this study is to provide a method for computing the following: Given a network of curves in 3d (satisfying a condition at the intersection points), compute efficiently a smooth surface such that the curves are geodesics on it.…

Computational Geometry · Computer Science 2024-06-04 Tom Gilat

In this paper, we show that there is a close relation between consistency in a constraint network and set intersection. A proof schema is provided as a generic way to obtain consistency properties from properties on set intersection. This…

Artificial Intelligence · Computer Science 2011-10-12 R. H. C. Yap , Y. Zhang

In this article we describe an algorithm that can be applied for the generation of various classes of maps on orientable surfaces. It uses existing generators for abstract graphs and combines them with an efficient embedding and isomorphism…

Combinatorics · Mathematics 2024-08-30 Gunnar Brinkmann

Two free homotopy classes of closed curves in an orientable surface with negative Euler characteristic are said to be length equivalent if for any hyperbolic structure on the surface, the length of the geodesic in one class is equal to the…

Geometric Topology · Mathematics 2013-11-05 Moira Chas

Let $S$ be a complete flat surface, such as the Euclidean plane. We determine the homeomorphism class of the space of all curves on $S$ which start and end at given points in given directions and whose curvatures are constrained to lie in a…

Geometric Topology · Mathematics 2025-10-28 Nicolau C. Saldanha , Pedro Zühlke

In this paper, we extend the method developed in [17, 18] to curves in the Minkowski plane. The method proposes a way to study deformations of plane curves taking into consideration their geometry as well as their singularities. We deal in…

Differential Geometry · Mathematics 2020-07-10 A. P. Francisco

Let $S$ be a complete flat surface, such as the Euclidean plane. We obtain direct characterizations of the connected components of the space of all curves on $S$ which start and end at given points in given directions, and whose curvatures…

Geometric Topology · Mathematics 2016-02-11 Nicolau C. Saldanha , Pedro Zühlke

A notion of dual curve for pseudoholomorphic curves in 4--manifolds turns out to be possible only if the notion of almost complex structure structure is slightly generalized. The resulting structure is as easy (perhaps easier) to work with,…

Differential Geometry · Mathematics 2007-05-23 Benjamin McKay