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An edge-unfolding of a polyhedron is produced by cutting along edges and flattening the faces to a *net*, a connected planar piece with no overlaps. A *grid unfolding* allows additional cuts along grid edges induced by coordinate planes…

Computational Geometry · Computer Science 2007-05-23 Mirela Damian , Robin Flatland , Joseph O'Rourke

We consider a generalization of the classical Art Gallery Problem, where instead of a light source, the guards, called $k$-transmitters, model a wireless device with a signal that can pass through at most $k$ walls. We show it is NP-hard to…

Computational Geometry · Computer Science 2020-04-15 Sarah Cannon , Thomas G. Fai , Justin Iwerks , Undine Leopold , Christiane Schmidt

A terrain is an x-monotone polygonal curve, i.e., successive vertices have increasing x-coordinates. Terrain Guarding can be seen as a special case of the famous art gallery problem where one has to place at most $k$ guards on a terrain…

Computational Geometry · Computer Science 2018-07-03 Édouard Bonnet , Panos Giannopoulos

We will consider some extensions of the polygonal art gallery problem. In a recent paper Morrison has shown the smallest (9 sides) example of an art gallery that cannot be observed by guards placed in every third corner. Author also…

Computational Geometry · Computer Science 2019-09-20 Eryk Lipka

We consider guarding classes of simple polygons using mobile guards (polygon edges and diagonals) under the constraint that no two guards may see each other. In contrast to most other art gallery problems, existence is the primary question:…

Computational Geometry · Computer Science 2012-06-11 Sarah Cannon , Diane L. Souvaine , Andrew Winslow

A hidden guard set $ G $ is a set of point guards in polygon $ P $ that all points of the polygon are visible from some guards in $ G $ under the constraint that no two guards may see each other. In this paper, we consider the problem for…

Computational Geometry · Computer Science 2017-08-22 Hamid Hoorfar , Alireza Bagheri

We explore the problem of $M$-guarding polygons with holes using $k$-visibility guards, where a set of guards is said to $M$-guard a polygon if every point in the polygon is visible to at least $M$ guards, with the constraint that there may…

Computational Geometry · Computer Science 2025-10-30 Yeganeh Bahoo , Ahmad Kamaludeen

We prove that, given a polyhedron $\mathcal P$ in $\mathbb{R}^3$, every point in $\mathbb R^3$ that does not see any vertex of $\mathcal P$ must see eight or more edges of $\mathcal P$, and this bound is tight. More generally, this remains…

Computational Geometry · Computer Science 2023-08-29 Csaba D. Tóth , Jorge Urrutia , Giovanni Viglietta

A polygonal art gallery can be observed by guards placed at one third of its corners. However, the strategy of placing guards at every third corner does not work for all art galleries. In this note, we provide an example of a nine-sided art…

Combinatorics · Mathematics 2019-08-06 Ralph Morrison

The chosen tool of this thesis is an extremal type approach. The lesson drawn by the theorems proved in the thesis is that surprisingly small compromise is necessary on the efficacy of the solutions to make the approach work. The problems…

Combinatorics · Mathematics 2017-11-09 Tamás Róbert Mezei

We study the Cooperative Guarding problem for polygons with holes in a mobile multi-agents setting. Given a set of agents, initially deployed at a point in a polygon with $n$ vertices and $h$ holes, we require the agents to collaboratively…

Distributed, Parallel, and Cluster Computing · Computer Science 2022-03-01 John Augustine , Srikkanth Ramachandran

Given a simple polygon $\cal P$, in the Art Gallery problem the goal is to find the minimum number of guards needed to cover the entire $\cal P$, where a guard is a point and can see another point $q$ when $\overline{pq}$ does not cross the…

Computational Geometry · Computer Science 2021-12-03 Arash Vaezi , Mohammad Ghodsi

We show that every orthogonal polyhedron of genus at most 2 can be unfolded without overlap while using only a linear number of orthogonal cuts (parallel to the polyhedron edges). This is the first result on unfolding general orthogonal…

Computational Geometry · Computer Science 2016-11-02 Mirela Damian , Erik Demaine , Robin Flatland , Joseph O'Rourke

The purpose of the current study is to investigate a special case of art gallery problem, namely Sculpture Garden Problem. In the said problem, for a given polygon $P$, the ultimate goal is to place the minimum number of guards to define…

Computational Geometry · Computer Science 2021-07-20 Marzieh Eskandari , Bahram Sadeghi Bigham

We study noncrossing geometric graphs and their disjoint compatible geometric matchings. Given a cycle (a polygon) P we want to draw a set of pairwise disjoint straight-line edges with endpoints on the vertices of P such that these new…

Combinatorics · Mathematics 2020-08-20 Alexander Pilz , Jonathan Rollin , Lena Schlipf , André Schulz

We provide a spectrum of results for the Universal Guard Problem, in which one is to obtain a small set of points ("guards") that are "universal" in their ability to guard any of a set of possible polygonal domains in the plane. We give…

Computational Geometry · Computer Science 2017-03-28 Sándor P. Fekete , Qian Li , Joseph S. B. Mitchell , Christian Scheffer

Symmetric edge polytopes of graphs are important object in Ehrhart theory,and have an application to Kuramoto models. In the present paper, we study the upper and lower bounds for the number of facets of symmetric edge polytopes of…

Combinatorics · Mathematics 2025-05-01 Aki Mori , Kenta Mori , Hidefumi Ohsugi

We prove that every three-dimensional polyhedron is uniquely determined by its dihedral angles and edge lengths, even if nonconvex or self-intersecting, under two plausible sufficient conditions: (i) the polyhedron has only convex faces and…

Geometric Topology · Mathematics 2023-07-28 Yunhi Cho , Seonhwa Kim

We investigate lower bounds for the number of ideal and finite vertices of right-angled hyperbolic polyhedra of finite volume. We use a geometric method of orthogonal gluings to establish new bounds in low dimensions, specifically…

Combinatorics · Mathematics 2026-04-01 Andrey Egorov

For a polygon P with n vertices, the vertex guarding problem asks for the minimum subset G of P's vertices such that every point in P is seen by at least one point in G. This problem is NP-complete and APX-hard. The first approximation…

Computational Geometry · Computer Science 2011-02-17 James King