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The game of Cops and Robbers is a well known game played on graphs. In this paper we consider the class of graphs of bounded diameter. We improve the strategy of cops and previously used probabilistic method which results in an improved…

Combinatorics · Mathematics 2019-12-17 Seyyed Aliasghar Hosseini , Fiachra Knox , Bojan Mohar

In the game of cops and robber, the cops try to capture a robber moving on the vertices of the graph. The minimum number of cops required to win on a given graph $G$ is called the cop number of $G$. The biggest open conjecture in this area…

Combinatorics · Mathematics 2018-09-25 Pawel Pralat , Nicholas Wormald

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 consider a variation of a cops and robbers game in which the cop---here referred to as "hunter"---is not constrained by the graph but must play in the dark against a "mole." We characterize the graphs---which we will call…

Combinatorics · Mathematics 2014-05-15 Natasha Komarov , Peter Winkler

The localization game is a variant of the game of Cops and Robber in which the robber is invisible and moves between adjacent vertices, but the cops can probe any $k$ vertices of the graph to obtain the distance between probed vertices and…

Combinatorics · Mathematics 2026-02-10 Vesna Iršič Chenoweth , Matija Skrt

Introduced by Harris, Insko, Prieto Langarica, Stoisavljevic, and Sullivan, the \emph{tipsy cop and drunken robber} is a variant of the cop and robber game on graphs in which the robber simply moves randomly along the graph, while the cop…

Probability · Mathematics 2024-03-13 Pamela E. Harris , Erik Insko , Florian Lehner

Let $\gamma_g(G)$ be the game domination number of a graph $G$. Rall conjectured that if $G$ is a traceable graph, then $\gamma_g(G) \le \left\lceil \frac{1}{2}n(G)\right\rceil$. Our main result verifies the conjecture over the class of…

Combinatorics · Mathematics 2020-10-28 Csilla Bujtás , Vesna Iršič , Sandi Klavžar

The game of Cops and Robbers on graphs is a well-studied pursuit--evasion model whose central parameter, the cop number, captures the minimum number of pursuers required to guarantee capture of an adversary on a given graph. While the cop…

Combinatorics · Mathematics 2025-10-09 Nicholas Crawford , Vesna Iršič Chenoweth

We investigate the game of cops and robber, played on a finite graph, between one cop and one robber. If the cop can force a win on a graph, the graph is called cop-win. We describe a procedure we call corner ranking, performed on a graph,…

Combinatorics · Mathematics 2017-03-14 David Offner , Kerry Ojakian

The game of Cops and Robbers is a pursuit-evasion game on graphs that has been extensively studied in finite settings, particularly through the concept of cop number. In this paper, we explore infinite variants of the game, focusing on the…

Combinatorics · Mathematics 2025-09-04 Kenzie Fontenot , Iris Nguyen , Cody Olsen

The traditional game of cops and robbers is played on undirected graph. Recently, the same game played on directed graph is getting attention by more and more people. We knew that if we forbid some subgraph we can bound the cop number of…

Combinatorics · Mathematics 2020-01-29 Mingrui Liu

In this paper we analyze and model three open problems posed by Harris, Insko, Prieto-Langarica, Stoisavljevic, and Sullivan in 2020 concerning the tipsy cop and robber game on graphs. The three different scenarios we model account for…

Combinatorics · Mathematics 2021-03-01 Viktoriya Bardenova , Vincent Ciarcia , Erik Insko

The game of cops and robber has been studied for many years. Denoting $\mathsf{Forb}(4K_1)$ to be the family of all graphs that contain no induced subgraph isomorphic to $4K_1$ (e.g., with independence number less than $4$), we prove that…

Combinatorics · Mathematics 2026-01-15 Zhaoyu Wu

We theoretically analyze the Cops and Robber Game for the first time in a multidimensional grid. It is shown that for an $n$-dimensional grid, at least $n$ cops are necessary to ensure capture of the robber. We also present a set of cop…

Discrete Mathematics · Computer Science 2015-06-12 Sayan Bhattacharya , Goutam Paul , Swagato Sanyal

We study a game of pursuit and evasion introduced by Seager in 2012, in which a cop searches the robber from outside the graph, using distance queries. A graph on which the cop wins is called locatable. In her original paper, Seager asked…

Combinatorics · Mathematics 2014-02-13 Richard A. B. Johnson , Sebastian Koch

A \emph{periodic graph} ${\cal G}=(G_0, G_1, G_2, \dots)$ with period $p$ is an infinite periodic sequence of graphs $G_i = G_{i + p} = (V,E_i)$, where $i \geq 0$. The graph $G=(V,\cup_i E_i)$ is called the footprint of ${\cal G}$.…

Combinatorics · Mathematics 2024-10-30 Jean-Lou De Carufel , Paola Flocchini , Nicola Santoro , Frédéric Simard

Let $G$ be a graph with the usual shortest-path metric. A graph is $\delta$-hyperbolic if for every geodesic triangle $T$, any side of $T$ is contained in a $\delta$-neighborhood of the union of the other two sides. A graph is chordal if…

Combinatorics · Mathematics 2015-05-22 A. Martínez-Pérez

In the game of cops and robber, the cops try to capture a robber moving on the vertices of the graph. The minimum number of cops required to win on a given graph $G$ is called the cop number of $G$. The biggest open conjecture in this area…

Combinatorics · Mathematics 2014-12-12 Pawel Pralat , Nick Wormald

We investigate a pursuit-evasion game on an undirected graph in which a robber, moving at a fixed constant speed, attempts to evade a team of cops who are blind to the robber's location and can quickly travel between any pair of vertices in…

Combinatorics · Mathematics 2025-12-01 Hector Buffière , Rutger Campbell , Kevin Hendrey , Sang-il Oum

We examine a version of the Cops and Robber (CR) game in which the robber is invisible, i.e., the cops do not know his location until they capture him. Apparently this game (CiR) has received little attention in the CR literature. We…

Discrete Mathematics · Computer Science 2015-03-19 Athanasios Kehagias , Dieter Mitsche , Pawel Pralat