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In the original Art Gallery Problem (AGP), one seeks the minimum number of guards required to cover a polygon $P$. We consider the Chromatic AGP (CAGP), where the guards are colored. As long as $P$ is completely covered, the number of…

Computational Geometry · Computer Science 2014-03-13 Sándor P. Fekete , Stephan Friedrichs , Michael Hemmer

We study the Art Gallery Problem under $k$-hop visibility in polyominoes. In this visibility model, two unit squares of a polyomino can see each other if and only if the shortest path between the respective vertices in the dual graph of the…

Computational Geometry · Computer Science 2024-12-25 Omrit Filtser , Erik Krohn , Bengt J. Nilsson , Christian Rieck , Christiane Schmidt

Recently, a natural variant of the Art Gallery problem, known as the \emph{Contiguous Art Gallery problem} was proposed. Given a simple polygon $P$, the goal is to partition its boundary $\partial P$ into the smallest number of contiguous…

Computational Geometry · Computer Science 2026-04-16 Sarita de Berg , Jacobus Conradi , Ivor van der Hoog , Eva Rotenberg

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

Guarding a polygon with few guards is an old and well-studied problem in computational geometry. Here we consider the following variant: We assume that the polygon is orthogonal and thin in some sense, and we consider a point $p$ to guard a…

Computational Geometry · Computer Science 2016-04-26 Therese Biedl , Saeed Mehrabi

We study the problem of placing a set $T$ of broadcast towers in a simple polygon $P$ in order for any point to locate itself in the interior of $P$. Let $V(p)$ denote the visibility polygon of a point $p$, as the set of all points $q \in…

Computational Geometry · Computer Science 2018-11-30 Prosenjit Bose , Jean-Lou De Carufel , Alina Shaikhet , Michiel Smid

The problem of vertex guarding a simple polygon was first studied by Subir K. Ghosh (1987), who presented a polynomial-time $O(\log n)$-approximation algorithm for placing as few guards as possible at vertices of a simple $n$-gon $P$, such…

Computational Geometry · Computer Science 2019-07-03 Stav Ashur , Omrit Filtser , Matthew J. Katz

We present approximation algorithms with O(n^3) processing time for the minimum vertex and edge guard problems in simple polygons. It is improved from previous O(n^4) time algorithms of Ghosh. For simple polygon, there are O(n^3) visibility…

Computational Geometry · Computer Science 2015-03-17 Dae-Sung Jang , Sun-Il Kwon

We are interested in the problem of guarding simple orthogonal polygons with the minimum number of $ r $-guards. The interior point $ p $ belongs an orthogonal polygon $ P $ is visible from $ r $-guard $ g $, if the minimum area rectangle…

Computational Geometry · Computer Science 2017-09-14 Hamid Hoorfar , Alireza Bagheri

We study the problem of colouring the vertices of a polygon, such that every viewer in it can see a unique colour. The goal is to minimise the number of colours used. This is also known as the conflict-free chromatic guarding problem with…

Computational Geometry · Computer Science 2020-04-07 Onur Çağırıcı , Subir Kumar Ghosh , Petr Hliněný , Bodhayan Roy

The Searchlight Scheduling Problem was first studied in 2D polygons, where the goal is for point guards in fixed positions to rotate searchlights to catch an evasive intruder. Here the problem is extended to 3D polyhedra, with the guards…

Computational Geometry · Computer Science 2015-03-19 Giovanni Viglietta

The Art Gallery Problem is one of the most well-known problems in Computational Geometry, with a rich history in the study of algorithms, complexity, and variants. Recently there has been a surge in experimental work on the problem. In this…

Computational Geometry · Computer Science 2016-02-16 Pedro J. de Rezende , Cid C. de Souza , Stephan Friedrichs , Michael Hemmer , Alexander Kröller , Davi C. Tozoni

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

In this paper, we consider the 1.5-dimensional orthogonal terrain guarding problem. In this problem, we assign an x-monotone chain T because each edge is either horizontal or vertical, and determine the minimal number of vertex guards for…

Computational Geometry · Computer Science 2018-05-10 Wei-Yu Lai , Tien-Ruey Hsiang

In this paper, we study grid-obstacle representations of graphs where we assign grid-points to vertices and define obstacles such that an edge exists if and only if an $xy$-monotone grid path connects the two endpoints without hitting an…

Computational Geometry · Computer Science 2017-08-31 Therese Biedl , Saeed Mehrabi

We prove that any compact semi-algebraic set is homeomorphic to the solution space of some art gallery problem. Previous works have established similar universality theorems, but holding only up to homotopy equivalence, rather than…

Computational Geometry · Computer Science 2023-05-30 Jack Stade , Jamie Tucker-Foltz

The paper focuses on two problems: (i) how to orient the edges of an undirected graph in order to maximize the number of ordered vertex pairs (x,y) such that there is a directed path from x to y, and (ii) how to orient the edges so as to…

Data Structures and Algorithms · Computer Science 2015-06-02 S. L. Hakimi , E. Schmeichel , Neal E. Young

The problem of searching a polygonal region for an unpredictably moving intruder by a set of stationary guards, each carrying an orientable laser, is known as the Searchlight Scheduling Problem. Determining the computational complexity of…

Computational Geometry · Computer Science 2015-03-20 Giovanni Viglietta

This thesis focuses on two concepts which are widely studied in the field of computational geometry. Namely, visibility and unit disk graphs. In the field of visibility, we have studied the conflict-free chromatic guarding of polygons, for…

Computational Geometry · Computer Science 2021-11-02 Onur Çağırıcı

Herein, we consider the continuous 1.5-dimensional(1.5D) terrain guarding problem with two-sided guarding. We provide an x-monotone chain T and determine the minimal number of vertex guards such that all points of T have been two-sided…

Computational Geometry · Computer Science 2018-05-08 Wei-Yu Lai , Tien-Ruey Hsiang