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A rectangle visibility graph (RVG) is represented by assigning to each vertex a rectangle in the plane with horizontal and vertical sides in such a way that edges in the graph correspond to unobstructed horizontal and vertical lines of…

Combinatorics · Mathematics 2022-08-29 John S. Caughman , Charles L. Dunn , Joshua D. Laison , Nancy Ann Neudauer , Colin L. Starr

Geometric graphs are a special kind of graph with geometric features, which are vital to model many scientific problems. Unlike generic graphs, geometric graphs often exhibit physical symmetries of translations, rotations, and reflections,…

Using a notation of corner between edges when graph has a fixed rotation, i.e. cyclical order of edges around vertices, we define combinatorial objects - combinatorial maps as pairs of permutations, one for vertices and one for faces.…

Combinatorics · Mathematics 2009-09-02 Dainis Zeps

Let $G=(V(G),E(G))$ be a simple graph, and let $U\subseteq V(G)$. Two distinct vertices $x,y\in U$ are $U$-mutually visible if $G$ contains a shortest $x$-$y$ path that is internally disjoint from $U$. $U$ is called a mutual-visibility set…

Combinatorics · Mathematics 2025-06-04 J. Leaños , M. Lomelí-Haro , Christophe Ndjatchi , L. M. Ríos-Castro

According to the requirement of general static obstacle detection, this paper proposes a compact vectorization representation approach of local static environments for unmanned ground vehicles. At first, by fusing the data of LiDAR and IMU,…

Robotics · Computer Science 2022-06-15 Haiming Gao , Qibo Qiu , Wei Hua , Xuebo Zhang , Zhengyong Han , Shun Zhang

Interval graphs, intersection graphs of segments on a real line (intervals), play a key role in the study of algorithms and special structural properties. Unit interval graphs, their proper subclass, where each interval has a unit length,…

Data Structures and Algorithms · Computer Science 2026-02-19 Jan Kratochvíl , Tomáš Masařík , Jana Novotná

Observability of an array of identical LTI systems with incommensurable output matrices is studied, where an array is called observable when identically zero relative outputs imply synchronized solutions for the individual systems. It is…

Dynamical Systems · Mathematics 2016-08-12 S. Emre Tuna

In this paper we extend the work of Rautenbach and Szwarcfiter by giving a structural characterization of graphs that can be represented by the intersection of unit intervals that may or may not contain their endpoints. A characterization…

Combinatorics · Mathematics 2014-05-19 Alan Shuchat , Randy Shull , Ann N. Trenk , Lee C. West

In the area of beyond-planar graphs, i.e. graphs that can be drawn with some local restrictions on the edge crossings, the recognition problem is prominent next to the density question for the different graph classes. For 1-planar graphs,…

Data Structures and Algorithms · Computer Science 2021-08-04 Henry Förster , Michael Kaufmann , Chrysanthi N. Raftopoulou

The geometry of the moduli space of stable spin curves is studied, with emphasis on its combinatorial properties. In this context, the standard graph theoretic framework is not just a book-keeping device: some purely combinatorial results…

Algebraic Geometry · Mathematics 2007-05-23 Lucia Caporaso , Cinzia Casagrande

For a connected graph $G$ and $X\subseteq V(G)$, we say that two vertices $u$, $v$ are $X$-visible if there is a shortest $u,v$-path $P$ with $V(P)\cap X \subseteq \{u,v\}$. If every two vertices from $X$ are $X$-visible, then $X$ is a…

Combinatorics · Mathematics 2025-05-27 Pakanun Dokyeesun , Csilla Bujtás

A combinatorial Gray code for a class of objects is a listing that contains each object from the class exactly once such that any two consecutive objects in the list differ only by a `small change'. Such listings are known for many…

Combinatorics · Mathematics 2024-07-31 Torsten Mütze

An obstacle representation of a graph is a mapping of the vertices onto points in the plane and a set of connected regions of the plane (called obstacles) such that the straight-line segment connecting the points corresponding to two…

In various application fields, such as fluid-, cell-, or crowd-simulations, spatial data structures are very important. They answer nearest neighbor queries which are instrumental in performing necessary computations for, e.g., taking the…

Combinatorics · Mathematics 2023-11-01 Martin Skrodzki , Ulrich Reitebuch , Alex McDonough

The identifiability problem arises naturally in a number of contexts in mathematics and computer science. Specific instances include local or global rigidity of graphs and unique completability of partially-filled tensors subject to rank…

Metric Geometry · Mathematics 2024-01-24 James Cruickshank , Fatemeh Mohammadi , Anthony Nixon , Shin-ichi Tanigawa

In this paper, we focus on graph learning from multi-view data of shared entities for spectral clustering. We can explain interactions between the entities in multi-view data using a multi-layer graph with a common vertex set, which…

Machine Learning · Computer Science 2021-03-04 Sravanthi Gurugubelli , Sundeep Prabhakar Chepuri

Given a planar graph $G$ and a partition of the neighbors of each vertex $v$ in four sets $UR(v)$, $UL(v)$, $DL(v)$, and $DR(v)$, the problem Windrose Planarity asks to decide whether $G$ admits a windrose-planar drawing, that is, a planar…

Graph clustering has been popularly studied in recent years. However, most existing graph clustering methods focus on node-level clustering, i.e., grouping nodes in a single graph into clusters. In contrast, graph-level clustering, i.e.,…

Machine Learning · Computer Science 2023-11-27 Mengling Hu , Chaochao Chen , Weiming Liu , Xinyi Zhang , Xinting Liao , Xiaolin Zheng

We study subclasses of grid intersection graphs from the perspective of order dimension. We show that partial orders of height two whose comparability graph is a grid intersection graph have order dimension at most four. Starting from this…

Combinatorics · Mathematics 2015-12-09 Steven Chaplick , Stefan Felsner , Udo Hoffmann , Veit Wiechert

Convolution-based and Transformer-based vision backbone networks process images into the grid or sequence structures, respectively, which are inflexible for capturing irregular objects. Though Vision GNN (ViG) adopts graph-level features…

Computer Vision and Pattern Recognition · Computer Science 2024-12-11 Jiafu Wu , Jian Li , Jiangning Zhang , Boshen Zhang , Mingmin Chi , Yabiao Wang , Chengjie Wang