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The cop number of a graph $G$ is the smallest $k$ such that $k$ cops win the game of cops and robber on $G$. We investigate the maximum cop number of geometric intersection graphs, which are graphs whose vertices are represented by…

A generalization of hyperopic cops and robber, analogous to the $k$-visibility cops and robber, is introduced in this paper. For a positive integer $k$ the $k$-hyperopic game of cops and robber is defined similarly as the usual cops and…

Combinatorics · Mathematics 2024-10-24 Nicholas Crawford , Vesna Iršič Chenoweth

The game of cops and robber is a pursuit-evasion game played on graphs that has been extensively studied. Traditionally the game is played with one or more cops and only one robber, but in this paper we consider the game played with…

Combinatorics · Mathematics 2025-09-15 Miha Gyergyek , Vesna Iršič Chenoweth

In many variants of the game of Cops and Robbers on graphs, multiple cops play against a single robber. In 2019, Cox and Sanaei introduced a variant of the game that gives the robber a more active role than simply evading the cop. In their…

Combinatorics · Mathematics 2022-05-17 Joshua Carlson , Meghan Halloran , Carolyn Reinhart

This paper considers the Cops and Attacking Robbers game, a variant of Cops and Robbers, where the robber is empowered to attack a cop in the same way a cop can capture the robber. In a graph $G$, the number of cops required to capture a…

Combinatorics · Mathematics 2024-08-06 Alexander Clow , Melissa A. Huggan , M. E. Messinger

We introduce the bodyguard problem for graphs. This is a variation of Surrounding Cops and Robber but, in this model, a smallest possible group of bodyguards must surround the president and then maintain this protection indefinitely. We…

Combinatorics · Mathematics 2025-08-15 Nancy E. Clarke , Danny Dyer , William Kellough

In the game of Cops and Robbers, one of the most useful results is that an isometric path in a graph can be guarded by one cop. In this paper, we introduce the concept of wide shadow in a subgraph, and use it to characterize all 1-guardable…

Combinatorics · Mathematics 2024-06-04 Sebastián González Hermosillo de la Maza , Bojan Mohar

We investigate extremal graphs related to the game of Cops and Robbers. We focus on graphs where a single cop can catch the robber; such graphs are called cop-win. The capture time of a cop-win graph is the minimum number of moves the cop…

Combinatorics · Mathematics 2019-03-21 David Offner , Kerry Ojakian

Here we merge the two fields of Cops and Robbers and Graph Pebbling to introduce the new topic of Cops and Robbers Pebbling. Both paradigms can be described by moving tokens (the cops) along the edges of a graph to capture a special token…

Combinatorics · Mathematics 2026-02-10 Nancy Clarke , Joshua Forkin , Glenn Hurlbert

We investigate multiple variants of the game Cops and Robbers. Playing it on an $n \times n$ toroidal chess graph, the game is varied by defining moves for cops and robbers differently, always mimicking moves of certain chess pieces. In…

Combinatorics · Mathematics 2018-10-26 Allyson Hahn , Neil R. Nicholson

We consider the cop-throttling number of a graph $G$ for the game of Cops and Robbers, which is defined to be the minimum of $(k + \text{capt}_k(G))$, where $k$ is the number of cops and $\text{capt}_k(G)$ is the minimum number of rounds…

Combinatorics · Mathematics 2018-02-27 Jane Breen , Boris Brimkov , Joshua Carlson , Leslie Hogben , K. E. Perry , Carolyn Reinhart

We show that the expected time for a smart "cop" to catch a drunk "robber" on an $n$-vertex graph is at most $n + {\rm o}(n)$. More precisely, let $G$ be a simple, connected, undirected graph with distinguished points $u$ and $v$ among its…

Combinatorics · Mathematics 2014-11-05 Natasha Komarov , Peter Winkler

We consider the effect on the length of the game of Cops and Robbers when more cops are added to the game play. In Overprescribed Cops and Robbers, as more cops are added, the capture time (the minimum length of the game assuming optimal…

Combinatorics · Mathematics 2016-11-24 Anthony Bonato , Xavier Pérez-Giménez , Paweł Prałat , Benjamin Reiniger

We consider a variation of the Cops and Robber game where the cops can only see the robber when the distance between them is at most a fixed parameter $\ell$. We consider the basic consequences of this definition for some simple graph…

Discrete Mathematics · Computer Science 2017-08-25 N. E. Clarke , D. Cox , C. Duffy , D. Dyer , S. Fitzpatrick , M. E. Messinger

We consider a variation of cop vs.\ robber on graph in which the robber is not restricted by the graph edges; instead, he picks a time-independent probability distribution on $V(G)$ and moves according to this fixed distribution. The cop…

Combinatorics · Mathematics 2013-08-23 Natasha Komarov , Peter Winkler

We define new graph parameters, called flip-width, that generalize treewidth, degeneracy, and generalized coloring numbers for sparse graphs, and clique-width and twin-width for dense graphs. The flip-width parameters are defined using…

Combinatorics · Mathematics 2024-03-26 Szymon Toruńczyk

We survey results at the intersection of topological graph theory and the game of Cops and Robbers, focusing on results, conjectures, and open problems for the cop number of a graph embedded on a surface. After a discussion on results for…

Combinatorics · Mathematics 2018-04-24 Anthony Bonato , Bojan Mohar

We consider the cops and robber game variant consisting of one cop and one robber on time-varying graphs (TVG). The considered TVGs are edge periodic graphs, i.e., for each edge, a binary string $s_e$ determines in which time step the edge…

Computational Complexity · Computer Science 2021-07-13 Nils Morawietz , Petra Wolf

We show that the cop number of every generalized Petersen graph is at most 4. The strategy is to play a modified game of cops and robbers on an infinite cyclic covering space where the objective is to capture the robber or force the robber…

We consider a cops and robber game where the cops are blocking edges of a graph, while the robber occupies its vertices. At each round of the game, the cops choose some set of edges to block and right after the robber is obliged to move to…

Discrete Mathematics · Computer Science 2020-09-09 Stratis Limnios , Christophe Paul , Joanny Perret , Dimitrios M. Thilikos