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Let $\gamma$ be a generic closed curve in the plane. Samuel Blank, in his 1967 Ph.D. thesis, determined if $\gamma$ is self-overlapping by geometrically constructing a combinatorial word from $\gamma$. More recently, Zipei Nie, in an…

Computational Geometry · Computer Science 2023-09-06 Hsien-Chih Chang , Brittany Terese Fasy , Bradley McCoy , David L. Millman , Carola Wenk

Van Goethem and Verbeek recently showed how to morph between two planar orthogonal drawings $\Gamma_I$ and $\Gamma_O$ of a connected graph $G$ while preserving planarity, orthogonality, and the complexity of the drawing during the morph.…

Computational Geometry · Computer Science 2019-08-23 Arthur van Goethem , Bettina Speckmann , Kevin Verbeek

Let $ S_g $ be a closed surface of genus $ g $ and let $ (\alpha, \beta) $ be a filling pair on $ S_g $; then $ i(\alpha, \beta) \geq 2g-1 $, where $ i $ is the (geometric) intersection number. Aougab and Huang demonstrated that…

Geometric Topology · Mathematics 2016-03-11 Mark Nieland

A hypergraph is linear if each pair of distinct vertices appears in at most one common edge. We say $\varGamma=(V,E)$ is an associated graph of a linear hypergraph $\mathcal{H}=(V, X)$ if for any $x\in X$, the induced subgraph…

Combinatorics · Mathematics 2025-03-25 Kai Yuan , Qi Wang , Rongquan Feng , Yan Wang

Let \Sigma = \Sigma _{g,1} be a compact surface of genus g at least 3 with one boundary component, \Gamma its mapping class group and M = H_1(\Sigma , Z) the first integral homology of \Sigma . Using that \Gamma is generated by the Dehn…

Algebraic Topology · Mathematics 2011-02-24 Rasmus Villemoes

Assume you are given a finite configuration $\Gamma$ of disjoint rectifiable Jordan curves in $\mathbb{R}^n$. The Plateau-Douglas problem asks whether there exists a minimizer of area among all compact surfaces of genus at most $p$ which…

Differential Geometry · Mathematics 2020-08-21 Paul Creutz , Martin Fitzi

We study topological properties of random closed curves on an orientable surface $S$ of negative Euler characteristic. Letting $\gamma_{n}$ denote the conjugacy class of the $n^{th}$ step of a simple random walk on the Cayley graph driven…

Geometric Topology · Mathematics 2022-11-17 Tarik Aougab , Jonah Gaster

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

The mapping class group of a surface $\S$ acts on the set of closed geodesics on $\S$. This action preserves self-intersection number. In this paper, we count the orbits of curves with at most $K$ self-intersections, for each $K \geq 1$.…

Geometric Topology · Mathematics 2016-07-20 Jenya Sapir

We describe algorithms to efficiently compute minimum $(s,t)$-cuts and global minimum cuts of undirected surface-embedded graphs. Given an edge-weighted undirected graph $G$ with $n$ vertices embedded on an orientable surface of genus $g$,…

Data Structures and Algorithms · Computer Science 2019-10-11 Erin W. Chambers , Jeff Erickson , Kyle Fox , Amir Nayyeri

We prove that for any infinite-type orientable surface S there exists a collection of essential curves {\Gamma} in S such that any homeomorphism that preserves the isotopy classes of the elements of {\Gamma} is isotopic to the identity. The…

Geometric Topology · Mathematics 2017-03-02 Jesus Hernandez Hernandez , Israel Morales , Ferran Valdez

A $\textit{regular polygon surface}$ $M$ is a surface graph $(\Sigma, \Gamma)$ together with a continuous map $\psi$ from $\Sigma$ into Euclidean 3-space which maps faces to regular Euclidean polygons. When $\Sigma$ is homeomorphic to the…

Combinatorics · Mathematics 2018-04-17 Ian M. Alevy

Let $G$ be a simple topological graph and let $\Gamma$ be a polyline drawing of $G$. We say that $\Gamma$ \emph{partially preserves the topology} of $G$ if it has the same external boundary, the same rotation system, and the same set of…

Computational Geometry · Computer Science 2018-09-24 Emilio Di Giacomo , Peter Eades , Giuseppe Liotta , Henk Meijer , Fabrizio Montecchiani

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

Given an undirected, edge-weighted graph G together with pairs of vertices, called pairs of terminals, the minimum multicut problem asks for a minimum-weight set of edges such that, after deleting these edges, the two terminals of each pair…

Data Structures and Algorithms · Computer Science 2016-11-24 Éric Colin de Verdière

Given a residually connected incidence geometry $\Gamma$ that satisfies two conditions, denoted $(B_1)$ and $(B_2)$, we construct a new geometry $H(\Gamma)$ with properties similar to those of $\Gamma$. This new geometry $H(\Gamma)$ is…

Combinatorics · Mathematics 2024-05-30 Claudio Alexandre Piedade , Philippe Tranchida

Given a weighted, undirected graph $G$ cellularly embedded on a topological surface $S$, we describe algorithms to compute the second shortest and third shortest closed walks of $G$ that are neither homotopically trivial in $S$ nor…

Computational Geometry · Computer Science 2025-07-22 Matthijs Ebbens , Francis Lazarus

The vertex connectivity of a graph $G$ is the size of the smallest set of vertices $S$ such that $G \setminus S$ is disconnected. For the class of planar graphs, the problem of vertex connectivity is well-studied, both from structural and…

Computational Geometry · Computer Science 2025-06-03 Therese Biedl , Karthik Murali

Circle graphs are intersection graphs of chords of a circle. In this paper, we present a new algorithm for the circle graph isomorphism problem running in time $O((n+m)\alpha(n+m))$ where $n$ is the number of vertices, $m$ is the number of…

Data Structures and Algorithms · Computer Science 2019-08-27 Vít Kalisz , Pavel Klavík , Peter Zeman

In this work, we study the cellular decomposition of $S$ induced by a filling pair of curves $v$ and $w$, $Dec_{v,w}(S) = S - (v \cup w)$, and its connection to the distance function $d(v,w)$ in the curve graph of a closed orientable…

Geometric Topology · Mathematics 2021-06-28 Joan S. Birman , Matthew J. Morse , Nancy C. Wrinkle