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Related papers: Cops and Robbers on diameter two graphs

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The cops and robbers game has been extensively studied under the assumption of optimal play by both the cops and the robbers. In this paper we study the problem in which cops are chasing a drunk robber (that is, a robber who performs a…

Discrete Mathematics · Computer Science 2017-01-09 Athanasios Kehagias , Pawel Pralat

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…

A hole in a graph is an induced cycle of length at least 4. We give a simple winning strategy for t-3 cops to capture a robber in the game of cops and robbers played in a graph that does not contain a hole of length at least t. This…

Combinatorics · Mathematics 2020-01-03 Vaidy Sivaraman

We prove that the cop number of any $2K_2$-free graph is at most 2, proving a conjecture of Sivaraman and Testa. We also show that the upper bound of $3$ on the cop number of $2K_1+K_2$-free (co-diamond--free) graphs is best possible.

Combinatorics · Mathematics 2025-10-29 Jérémie Turcotte

The game of cops and robber is a two-player turn-based game played on a graph where the cops try to capture the robber. The cop number of a graph $G$, denoted by $c(G)$ is the minimum number of cops required to capture the robber. For a…

Discrete Mathematics · Computer Science 2025-05-22 Arnab Char , Paras Vinubhai Maniya , Dinabandhu Pradhan

We study a variation of the classical pursuit-evasion game of Cops and Robbers in which agents are required to move to an adjacent vertex on every turn. We explore how the minimum number of cops needed to catch the robber can change when…

Combinatorics · Mathematics 2018-08-22 Ilya Gromovikov , William B. Kinnersley , Ben Seamone

In the classical cop and robber game, two players, the cop C and the robber R, move alternatively along edges of a finite graph G. The cop captures the robber if both players are on the same vertex at the same moment of time. A graph G is…

Discrete Mathematics · Computer Science 2015-03-17 Jérémie Chalopin , Victor Chepoi , Nicolas Nisse , Yann Vaxès

In the cops and robber games played on a simple graph $G$, Aigner and Fromme's lemma states that one cop can guard a shortest path in the sense that the robber cannot enter this path without getting caught after finitely many steps. In this…

Combinatorics · Mathematics 2018-04-11 Linyuan Lu , Zhiyu Wang

We compare two kinds of pursuit-evasion games played on graphs. In Cops and Robbers, the cops can move strategically to adjacent vertices as they please, while in a new variant, called deterministic Zombies and Survivors, the zombies (the…

Combinatorics · Mathematics 2018-09-11 David Offner , Kerry Ojakian

We explore a variant of the game of Cops and Robber introduced by Bonato et al.~where the robber is invisible unless outside the common neighbourhood of the cops. The hyperopic cop number is analogous to the cop number and we investigate…

Combinatorics · Mathematics 2021-07-16 Nancy E. Clarke , Stephen Finbow , Margaret-Ellen Messinger , Amanda Porter

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

This paper considers a game in which a single cop and a single robber take turns moving along the edges of a given graph $G$. If there exists a strategy for the cop which enables it to be positioned at the same vertex as the robber…

Data Structures and Algorithms · Computer Science 2019-08-20 Thomas Erlebach , Jakob T. Spooner

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

In this paper, the notions of {\em trapping} and {\em confining} the robber on a graph are introduced. We present some structural necessary conditions for graphs $G$ not containing the path on $k$ vertices (referred to as $P_k$-free graphs)…

Combinatorics · Mathematics 2020-09-15 Masood Masjoody

We consider a variant of Cops and Robbers in which the robber may traverse as many edges as he likes in each turn, with the constraint that he cannot pass through any vertex occupied by a cop. We study this model on several classes of…

Combinatorics · Mathematics 2022-05-17 William B. Kinnersley , Nikolas Townsend

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 study the problem of cops and robbers on the grid where the robber is allowed to move faster than the cops. It is well known that two cops are necessary and sufficient to catch the robber on any finite grid when the robber has unit…

Combinatorics · Mathematics 2017-06-06 Paul Balister , Béla Bollobás , Bhargav Narayanan , Amy Shaw

We introduce and study the Generalized Cops and Robbers game (GCR), an N-player pursuit game in graphs. The two-player version is essentially equivalent to the classic Cops and Robbers (CR) game. The three-player version can be understood…

Discrete Mathematics · Computer Science 2018-07-24 Athanasios Kehagias

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

The localization game is a two player combinatorial game played on a graph $G=(V,E)$. The cops choose a set of vertices $S_1 \subseteq V$ with $|S_1|=k$. The robber then chooses a vertex $v \in V$ whose location is hidden from the cops, but…

Combinatorics · Mathematics 2022-09-07 Lyuben Lichev , Dieter Mitsche , Pawel Pralat
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