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We consider the following distributed pursuit-evasion problem. A team of mobile agents called searchers starts at an arbitrary node of an unknown $n$-node network. Their goal is to execute a search strategy that guarantees capturing a fast…

Discrete Mathematics · Computer Science 2021-01-19 Dariusz Dereniowski , Dorota Urbańska

We extend the concept of polynomial time approximation algorithms to apply to problems for hierarchically specified graphs, many of which are PSPACE-complete. Assuming P != PSPACE, the existence or nonexistence of such efficient…

Combinatorics · Mathematics 2016-09-06 Madhav V. Marathe , Harry B. Hunt , S. S. Ravi

This paper addresses the problem of tracking mobile intruders in a polygonal environment. We assume that a team of diagonal guards is deployed inside the polygon to provide mobile coverage. First, we formulate the problem of tracking a…

Computational Geometry · Computer Science 2018-07-24 Guillermo J. Laguna , Sourabh Bhattacharya

In public transport networks disruptions may occur and lead to travel delays. It is thus interesting to determine whether a traveler can be resilient to delays that occur unexpectedly, ensuring that they can reach their destination in time…

Computational Complexity · Computer Science 2023-08-24 Thomas Depian , Christoph Kern , Sebastian Röder , Soeren Terziadis , Markus Wallinger

Given a geometric domain $P$, visibility-based search problems seek routes for one or more mobile agents ("watchmen") to move within $P$ in order to be able to see a portion (or all) of $P$, while optimizing objectives, such as the…

Computational Geometry · Computer Science 2025-06-03 Kien C. Huynh , Joseph S. B. Mitchell , Linh Nguyen , Valentin Polishchuk

Recently dictionary screening has been proposed as an effective way to improve the computational efficiency of solving the lasso problem, which is one of the most commonly used method for learning sparse representations. To address today's…

Machine Learning · Computer Science 2016-08-29 Yun Wang , Peter J. Ramadge

Visibility plays an important role for decision making in cluttered, uncertain environments. This paper considers the problem of identifying optimal hiding spots for an agent against line-of-sight detection by an adversary whose location is…

Optimization and Control · Mathematics 2026-02-02 Neilabh Banzal , Jorge Cortés , Sonia Martínez

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

We study a new modification of the Arrival problem, which allows for nodes that exhibit random as well as controlled behaviour, in addition to switching nodes. We study the computational complexity of these extensions, building on existing…

Computational Complexity · Computer Science 2024-09-17 Thomas Webster

This paper introduces a novel $k$-cell decomposition method for pursuit-evasion problems in polygonal environments, where a searcher is equipped with a $k$-modem: a device capable of seeing through up to $k$ walls. The proposed…

Computational Geometry · Computer Science 2025-11-06 Yeganeh Bahoo , Sajad Saeedi , Roni Sherman

Consider a sliding camera that travels back and forth along an orthogonal line segment $s$ inside an orthogonal polygon $P$ with $n$ vertices. The camera can see a point $p$ inside $P$ if and only if there exists a line segment containing…

Computational Geometry · Computer Science 2013-10-01 Stephane Durocher , Omrit Filtser , Robert Fraser , Ali Mehrabi , Saeed Mehrabi

In subset selection we search for the best linear predictor that involves a small subset of variables. From a computational complexity viewpoint, subset selection is NP-hard and few classes are known to be solvable in polynomial time. Using…

Optimization and Control · Mathematics 2020-02-07 Alberto Del Pia , Santanu S. Dey , Robert Weismantel

We introduce and study a general scheduling problem that we term the Packing Scheduling problem. In this problem, jobs can have different arrival times and sizes; a scheduler can process job $j$ at rate $x_j$, subject to arbitrary packing…

Data Structures and Algorithms · Computer Science 2014-04-07 Sungjin Im , Janardhan Kulkarni , Kamesh Munagala

We consider a variant of the art gallery problem where all guards are limited to seeing to the right inside a monotone polygon. We call such guards: half-guards. We provide a polynomial-time approximation for point guarding the entire…

Computational Geometry · Computer Science 2022-04-29 Hannah Miller Hillberg , Erik Krohn , Alex Pahlow

Partially ordered models of time occur naturally in applications where agents or processes cannot perfectly communicate with each other, and can be traced back to the seminal work of Lamport. In this paper we consider the problem of…

Computational Complexity · Computer Science 2023-05-26 Leif Eriksson , Victor Lagerkvist

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

The non-clairvoyant scheduling problem has gained new interest within learning-augmented algorithms, where the decision-maker is equipped with predictions without any quality guarantees. In practical settings, access to predictions may be…

Machine Learning · Computer Science 2024-08-06 Ziyad Benomar , Vianney Perchet

Opacity is a property of privacy and security applications asking whether, given a system model, a passive intruder that makes online observations of system's behaviour can ascertain some "secret" information of the system. Deciding opacity…

Formal Languages and Automata Theory · Computer Science 2023-04-21 Jiří Balun , Tomáš Masopust , Petr Osička

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

There exist many variants of guarding an orthogonal polygon in an orthogonal fashion: sometimes a guard can see an entire rectangle, or along a staircase, or along an orthogonal path with at most $k$ bends. In this paper, we study all these…

Computational Geometry · Computer Science 2017-06-08 Therese Biedl , Saeed Mehrabi