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A polyhedral surface~$\mathcal{C}$ in $\mathbb{R}^3$ with convex polygons as faces is a side-contact representation of a graph~$G$ if there is a bijection between the vertices of $G$ and the faces of~$\mathcal{C}$ such that the polygons of…

Computational Geometry · Computer Science 2023-08-02 André Schulz

Let X be a closed oriented Riemann surface of genus > 1 of constant negative curvature -1. A surface containing a disk of maximal radius is an optimal surface. This paper gives exact formulae for the number of optimal surfaces of genus > 3…

Geometric Topology · Mathematics 2009-04-14 Alina Vdovina

After defining convex near-polygons, a formula enumerating the number of triangulations of such configurations is derived in terms of edge-polynomials. The paper describes also a transfer-matrix approach for computing quantities related to…

Combinatorics · Mathematics 2007-05-23 Roland Bacher

We prove that for every surface $\Sigma$ of Euler genus $g$, every edge-maximal embedding of a graph in $\Sigma$ is at most $O(g)$ edges short of a triangulation of $\Sigma$. This provides the first answer to an open problem of Kainen…

Combinatorics · Mathematics 2019-08-13 Colin McDiarmid , David R. Wood

We consider triangulations of closed $2$-dimensional (not necessarily orientable) surfaces. Any minimal set of zigzags that double covers the set of edges provides a $z$-orientation of the triangulation. We introduce Markov chains of…

Combinatorics · Mathematics 2026-01-27 Adam Tyc

We present a formula expressing Earle's twisted 1-cocycle on the mapping class group of a closed oriented surface of genus >=2 relative to a fixed base point, with coefficients in the first homology group of the surface. For this purpose we…

Geometric Topology · Mathematics 2008-12-12 Yusuke Kuno

We study edge-maximal, non-complete graphs on surfaces that do not triangulate the surface. We prove that there is no such graph on the projective plane $\mathbb{N}_1$, $K_7-e$ is the unique such graph on the Klein bottle $\mathbb{N}_2$ and…

Combinatorics · Mathematics 2019-11-11 James Davies , Florian Pfender

A well-known result of Walsh states that if $\mathcal T^*$ is an ideal triangulation of an atoroidal, acylindrical, irreducible, compact 3-manifold with torus boundary components, then every properly embedded, two-sided, incompressible…

Geometric Topology · Mathematics 2025-06-09 Birch Bryant

We describe an infinite family of edge-decompositions of complete graphs into two graphs, each of which triangulate the same orientable surface. Previously, such decompositions had only been known for only a few complete graphs. These…

Combinatorics · Mathematics 2021-11-24 Timothy Sun

Let $D$ be a directed graphs with distinguished sets of sources $S\subseteq V(D)$ and sinks $T\subseteq V(D)$. A tripod in $D$ is a subgraph consisting of the union of two $S$-$T$-paths that have distinct start-vertices and the same…

Combinatorics · Mathematics 2024-08-30 Marcin Briański , Meike Hatzel , Karolina Okrasa , Michał Pilipczuk

An obstacle representation of a plane graph G is V(G) together with a set of opaque polygonal obstacles such that G is the visibility graph on V(G) determined by the obstacles. We investigate the problem of computing an obstacle…

Computational Geometry · Computer Science 2011-08-15 Matthew P. Johnson , Deniz Sarioz

We prove that every triangulation of either of the torus, projective plane and Klein bottle, contains a vertex-spanning planar Laman graph as a subcomplex. Invoking a result of Kir{\'a}ly, we conclude that every $1$-skeleton of a…

Combinatorics · Mathematics 2022-05-03 Eran Nevo , Simion Tarabykin

Trivalent $2$-stratifolds are a generalization of $2$-manifolds in that there are disjoint simple closed curves where three sheets meet. We develop operations on their associated labeled graphs that will effectively construct from a single…

Geometric Topology · Mathematics 2018-05-17 J. C. Gómez-Larrañaga , F. González-Acuña , Wolfgang Heil , Y. A. Hernández-Esparza

We restrict our discussion to the orientable category. For $g > 1$, let $OE_g$ be the maximum order of a finite group $G$ acting on the closed surface $\Sigma_g$ of genus $g$ which extends over $(S^3, \Sigma_g)$, where the maximum is taken…

Geometric Topology · Mathematics 2016-06-07 Chao Wang , Shicheng Wang , Yimu Zhang , Bruno Zimmermann

We describe an algorithm for the enumeration of (candidates of) vertex-transitive combinatorial $d$-manifolds. With an implementation of our algorithm, we determine, up to combinatorial equivalence, all combinatorial manifolds with a…

Geometric Topology · Mathematics 2007-05-23 Ekkehard G. Köhler , Frank H. Lutz

We introduce series-triangular graph embeddings and show how to partition point sets with them. This result is then used to improve the upper bound on the number of Steiner points needed to obtain compatible triangulations of point sets.…

Computational Geometry · Computer Science 2007-05-23 Jeff Danciger , Satyan L. Devadoss , Don Sheehy

We characterise the quotient surface graphs arising from symmetric contact systems of line segments in the plane and also from symmetric pointed pseudotriangulations in the case where the group of symmetries is generated by a translation or…

Combinatorics · Mathematics 2022-03-22 James Cruickshank , Bernd Schulze

Let $X$ be a quadratic vector field with a center whose generic orbits are algebraic curves of genus one. To each $X$ we associate an elliptic surface (a smooth complex compact surface which is a genus one fibration). We give the list of…

Dynamical Systems · Mathematics 2008-01-29 Sebastien Gautier

We survey basic properties and bounds for $q$-equivelar and $d$-covered triangulations of closed surfaces. Included in the survey is a list of the known sources for $q$-equivelar and $d$-covered triangulations. We identify all orientable…

Combinatorics · Mathematics 2010-01-19 Frank H. Lutz , Thom Sulanke , Anand K. Tiwari , Ashish K. Upadhyay

For a graph $G$, let $\mathbb{D}(G)$ denote the set of all strong orientations of $G$, and the oriented diameter of $G$ is $f(G)=\min \{diam(D) \mid D \in \mathbb{D}(G)\}$, which is the minimum value of the diameters $diam(D)$ where $D \in…

Combinatorics · Mathematics 2025-02-11 Jing Liu , Hui Zhou