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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

Untangling is a process in which some vertices of a planar graph are moved to obtain a straight-line plane drawing. The aim is to move as few vertices as possible. We present an algorithm that untangles the cycle graph C_n while keeping at…

Computational Geometry · Computer Science 2011-02-07 Josef Cibulka

In 2006, Barat and Thomassen conjectured in 2006 that the edges of every planar 4-regular 4-edge-connected graph can be decomposed into copies of the star with 3 leaves. Shortly afterward, Lai constructed a counterexample to this…

Combinatorics · Mathematics 2018-04-02 Michelle Delcourt , Luke Postle

The notion of 1-planarity is among the most natural and most studied generalizations of graph planarity. A graph is 1-planar if it has an embedding where each edge is crossed by at most another edge. The study of 1-planar graphs dates back…

Computational Geometry · Computer Science 2017-07-21 Stephen G. Kobourov , Giuseppe Liotta , Fabrizio Montecchiani

A biclique of a graph $G$ is an induced complete bipartite subgraph of $G$ such that neither part is empty. A star is a biclique of $G$ such that one part has exactly one vertex. The star graph of $G$ is the intersection graph of the…

We describe the most general homogenous, planar, light-ray-direction-changing sheet that performs one-to-one imaging between object space and image space. This is a non-trivial special case (of the sheet being homogenous) of an earlier…

Optics · Physics 2015-06-17 Stephen Oxburgh , Johannes Courtial

We prove a novel method for the embedding of a 3-fold rotationally symmetric sphere-type mesh onto a subset of the plane with 3-fold rotational symmetry. The embedding is free-boundary with the only additional constraint on the image set is…

Computational Geometry · Computer Science 2024-06-12 Tom Gilat , Ben Gilat

Simplicial surfaces describe the incidence relations between vertices, edges and faces of triangulated 2-dimensional manifolds in a purely combinatorial way. By considering only the incidences of edges and faces, simplicial surfaces are…

Combinatorics · Mathematics 2025-06-26 Meike Weiß , Alice C. Niemeyer

This work studies certain aspects of graphs embedded on surfaces. Initially, a colored graph model for a map of a graph on a surface is developed. Then, a concept analogous to (and extending) planar graph is introduced in the same spirit as…

Combinatorics · Mathematics 2007-05-23 Sostenes Lins

In this paper, we have examined the problem of embedding a cycle of n vertices onto a given set of n points inside a simple polygon. The goal of the problem is that the cycle must be embedded without bends and does not intersect itself and…

Computational Geometry · Computer Science 2022-06-24 Maryam Fadavian , Heidar Fadavian

In the graph node embedding problem, embedding spaces can vary significantly for different data types, leading to the need for different GNN model types. In this paper, we model the embedding update of a node feature as a Hamiltonian orbit…

Machine Learning · Computer Science 2023-05-31 Qiyu Kang , Kai Zhao , Yang Song , Sijie Wang , Wee Peng Tay

In this paper we give a lower bound for the least distortion embedding of a distance regular graph into Euclidean space. We use the lower bound for finding the least distortion for Hamming graphs, Johnson graphs, and all strongly regular…

Combinatorics · Mathematics 2007-11-14 Frank Vallentin

A digraph is 2-regular if every vertex has both indegree and outdegree two. We define an embedding of a 2-regular digraph to be a 2-cell embedding of the underlying graph in a closed surface with the added property that for every…

Combinatorics · Mathematics 2017-06-12 Dan Archdeacon , Matt DeVos , Stefan Hannie , Bojan Mohar

This paper introduces a novel topology, referred to as the star topology, on finite graphs. By treating vertices and edges as points in a unified space, we explore continuous maps between Bare representations of a graph and their…

Combinatorics · Mathematics 2025-07-21 Rodolfo E. Maza

We show that c-planarity is solvable in quadratic time for flat clustered graphs with three clusters if the combinatorial embedding of the underlying graph is fixed. In simpler graph-theoretical terms our result can be viewed as follows.…

Computational Geometry · Computer Science 2016-08-26 Radoslav Fulek

We present a data structure that can maintain a simple planar graph under edge contractions in linear total time. The data structure supports adjacency queries and provides access to neighbor lists in $O(1)$ time. Moreover, it can report…

Data Structures and Algorithms · Computer Science 2017-07-03 Jacob Holm , Giuseppe F. Italiano , Adam Karczmarz , Jakub Łącki , Eva Rotenberg , Piotr Sankowski

Low-dimensional representations, or embeddings, of a graph's nodes facilitate several practical data science and data engineering tasks. As such embeddings rely, explicitly or implicitly, on a similarity measure among nodes, they require…

Machine Learning · Computer Science 2023-01-06 Anton Tsitsulin , Marina Munkhoeva , Davide Mottin , Panagiotis Karras , Ivan Oseledets , Emmanuel Müller

We associate root polytopes to directed graphs and study them by using ribbon structures. Most attention is paid to what we call the semi-balanced case, i.e., when each cycle has the same number of edges pointing in the two directions.…

Combinatorics · Mathematics 2024-08-16 Tamás Kálmán , Lilla Tóthmérész

A monotone drawing of a planar graph $G$ is a planar straight-line drawing of $G$ where a monotone path exists between every pair of vertices of $G$ in some direction. Recently monotone drawings of planar graphs have been proposed as a new…

Computational Geometry · Computer Science 2013-10-24 Md. Iqbal Hossain , Md. Saidur Rahman

Let $\cal R$ be an ordered vector space over an ordered division ring. We prove that every definable set $X$ is a finite union of relatively open definable subsets which are definably simply-connected, settling a conjecture from [5]. The…

Logic · Mathematics 2019-10-02 Pantelis E. Eleftheriou