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The directions of an infinite graph $G$ are a tangle-like description of its ends: they are choice functions that choose compatibly for all finite vertex sets $X\subseteq V(G)$ a component of $G-X$. Although every direction is induced by a…

Combinatorics · Mathematics 2021-01-19 Jan Kurkofka , Ruben Melcher

Let $\Sigma$ denote a closed surface with constant mean curvature in $\mathbb{G}^3$, a 3-dimensional Lie group equipped with a bi-invariant metric. For such surfaces, there is a harmonic Gauss map which maps values to the unit sphere within…

Differential Geometry · Mathematics 2026-01-22 Alcides de Carvalho , Marcos P. Cavalcante , Wagner Costa-Filho , Darlan de Oliveira

We present a combinatorial characterization of the Bethe entropy function of a factor graph, such a characterization being in contrast to the original, analytical, definition of this function. We achieve this combinatorial characterization…

Information Theory · Computer Science 2013-11-05 Pascal O. Vontobel

Word embeddings are representations of individual words of a text document in a vector space and they are often use- ful for performing natural language pro- cessing tasks. Current state of the art al- gorithms for learning word embeddings…

Computation and Language · Computer Science 2018-05-15 Prathusha Kameswara Sarma , Bill Sethares

A signed graph is a graph $G$ associated with a mapping $\sigma: E(G)\to \{-1,+1\}$, denoted by $(G,\sigma)$. A $cycle$ of $(G,\sigma)$ is a connected 2-regular subgraph. A cycle $C$ is $positive$ if it has an even number of negative edges,…

Combinatorics · Mathematics 2018-03-09 Yezhou Wu , Dong Ye

A simple graph $G=(V,E)$ is a $(2,1)$-circuit if $|E|=2|V|$ and $|E(H)|\leq 2|V(H)|-1$ for every proper subgraph $H$ of $G$. Motivated, in part, by ongoing work to understand unique realisations of graphs on surfaces, we derive a…

Combinatorics · Mathematics 2018-01-09 Thomas A McCourt , Anthony Nixon

Median graphs are connected graphs in which for all three vertices there is a unique vertex that belongs to shortest paths between each pair of these three vertices. In this paper we provide several novel characterizations of planar median…

Combinatorics · Mathematics 2021-10-19 Carsten R. Seemann , Vincent Moulton , Peter F. Stadler , Marc Hellmuth

Topological order of a topological phase of matter in two spacial dimensions is encoded by a unitary modular (tensor) category (UMC). A group symmetry of the topological phase induces a group symmetry of its corresponding UMC. Gauging is a…

Quantum Algebra · Mathematics 2017-04-25 Shawn X. Cui , César Galindo , Julia Yael Plavnik , Zhenghan Wang

Near a singular point of a surface or a curve, geometric invariants diverge in general, and the orders of diverge, in particular the boundedness about these invariants represent geometry of the surface and the curve. In this paper, we study…

Differential Geometry · Mathematics 2024-10-14 Luciana F. Martins , Kentaro Saji , Samuel P. dos Santos , Keisuke Teramoto

A \emph{geometric graph} is a graph whose vertex set is a set of points in general position in the plane, and its edges are straight line segments joining these points. We show that for every integer $k \ge 2$, there exists a constat $c>0$…

Computational Geometry · Computer Science 2023-11-01 Ruy Fabila-Monroy

A 2-edge-coloured graph $G$ is called {\bf locally complete} if for each vertex $v$, the vertices adjacent to $v$ through edges of the same colour induce a complete subgraph in $G$. Locally complete 2-edge-coloured graphs have nice…

Combinatorics · Mathematics 2024-10-08 Jørgen Bang-Jensen , Jing Huang

An arithmetical structure on a graph is given by a labeling of the vertices which satisfies certain divisibility properties. In this note, we look at several families of graphs and attempt to give counts on the number of arithmetical…

Combinatorics · Mathematics 2019-03-05 Darren Glass , Joshua Wagner

Along cuspidal edge singularities on a given surface in Euclidean 3-space, which can be parametrized by a regular space curve, a unit normal vector field $\nu$ is well-defined as a smooth vector field of the surface. A cuspidal edge…

Differential Geometry · Mathematics 2014-08-20 Kosuke Naokawa , Masaaki Umehara , Kotaro Yamada

We present a certified algorithm based on subdivision for computing an isotopic approximation to any number of curves in the plane. Our algorithm is based on the certified curve approximation algorithm of Plantinga and Vegter. The main…

Computational Geometry · Computer Science 2024-07-26 Michael Burr , Michael Byrd

We present a certified algorithm based on subdivision for computing an isotopic approximation to any number of curves in the plane. Our algorithm is based on the certified curve approximation algorithm of Plantinga and Vegter. The main…

Computational Geometry · Computer Science 2024-07-29 Michael Burr , Michael Byrd

Special generic maps are generalizations of Morse functions with exactly two singular points on spheres and canonical projections of unit spheres. They restrict the manifolds of the domains strongly in considerable cases and are important…

Algebraic Topology · Mathematics 2023-03-01 Naoki Kitazawa

Let F be a closed orientable surface. We give an explicit formula for the number mod 2 of quadruple points occurring in any generic regular homotopy between any two regularly homotopic embeddings e,e':F -> R^3. The formula is in terms of…

Geometric Topology · Mathematics 2007-05-23 Tahl Nowik

Graphs, such as social networks, word co-occurrence networks, and communication networks, occur naturally in various real-world applications. Analyzing them yields insight into the structure of society, language, and different patterns of…

Social and Information Networks · Computer Science 2019-08-22 Palash Goyal , Emilio Ferrara

The vertices of a finite state system are usually a subset of the natural numbers. Most algorithms relative to these systems only use this fact to select vertices. For infinite state systems, however, the situation is different: in…

Formal Languages and Automata Theory · Computer Science 2009-11-18 Christophe Morvan

A \emph{self-complementary} graph is a graph isomorphic to its complement. An isomorphism between $G$ and its complement, viewed as a permutation of $V(G)$, is then called an \emph{antimorphism}. A \emph{skew partition} of $G$ is a…

Combinatorics · Mathematics 2013-08-29 Nicolas Trotignon