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Cops and Robbers is a pursuit-evasion game played on graphs, of which many variants have been developed and studied. We introduce a variant of this game, "Sneaky-Active Cops and Robbers", where all cops and robber must move on their turn,…

Combinatorics · Mathematics 2026-03-16 Tien Chih , Laura Scull

In 2019, Sivaraman conjectured that every $P_k$-free graph has cop number at most $k-3$. In the same year, Liu proved this conjecture for $(P_k,\text{claw})$-free graphs. Recently Chudnovsky, Norin, Seymour, and Turcotte proved this…

Combinatorics · Mathematics 2025-09-16 Alexander Clow , Erin Meger

We present two efficient algorithms that compute the optimal strategy for cop in the game of Cop v.s. Gambler where the gambler's strategy is not optimal but known to the cop. The first algorithm is analogous to Bellman-Ford algorithm for…

Combinatorics · Mathematics 2017-01-11 Shen-Fu Tsai

We prove that every connected $P_5$-free graph has cop number at most two, solving a conjecture of Sivaraman. In order to do so, we first prove that every connected $P_5$-free graph $G$ with independence number at least three contains a…

Combinatorics · Mathematics 2025-10-29 Maria Chudnovsky , Sergey Norin , Paul Seymour , Jérémie Turcotte

In this note, we prove that all cop-win graphs G in the game in which the robber and the cop move at different speeds s and s' with s'<s, are \delta-hyperbolic with \delta=O(s^2). We also show that the dependency between \delta and s is…

Combinatorics · Mathematics 2018-12-12 Jérémie Chalopin , Victor Chepoi , Panos Papasoglu , Timothée Pecatte

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

We study the game of Cops and Robbers, where cops try to capture a robber on the vertices of a graph. Meyniel's conjecture states that for every connected graph $G$ on $n$ vertices, the cop number of $G$ is upper bounded by $O(\sqrt{n})$,…

Combinatorics · Mathematics 2019-09-09 Fatemeh Hasiri , Igor Shinkar

"Zombies and Survivor" is a variant of the well-studied game of "Cops and Robber" where the zombies (cops) can only move closer to the survivor (robber). We consider the deterministic version of the game where a zombie can choose their path…

Combinatorics · Mathematics 2021-06-04 Valentin Bartier , Laurine Bénéteau , Marthe Bonamy , Hoang La , Jonathan Narboni

The deduction game is a variation of the game of cops and robber on graphs in which searchers must capture an invisible evader in at most one move. Searchers know each others' initial locations, but can only communicate if they are on the…

Combinatorics · Mathematics 2024-12-24 Andrea Burgess , Danny Dyer , Mozhgan Farahani

Various models to quantify the reliability of a network have been studied where certain components of the graph may fail at random and the probability that the remaining graph is connected is the proxy for reliability. In this work we…

Combinatorics · Mathematics 2020-11-24 Maimoonah Ahmed , Ben Cameron

We introduce a new game played on graphs, ``Agents and Adversary". This game is reminiscent of ``Cops and Robbers" but has some fundamental differences. We classify infinite families of graphs as Agents-win and Adversary-win. We then define…

Combinatorics · Mathematics 2026-03-13 William K. Moses , Amanda Redlich , Frederick Stock

We consider the model of limited visibility Cops and Robbers, where the cops can only see within their $l$-neighbourhood. We prove that the number of cops needed to see the robber can be arbitrarily smaller than the number needed to capture…

Combinatorics · Mathematics 2025-07-02 Bojan Bašić , Alfie Davies , Aleksa Džuklevski , Strahinja Gvozdić , Yannick Mogge

The guarding game is a game in which several cops try to guard a region in a (directed or undirected) graph against Robber. Robber and the cops are placed on the vertices of the graph; they take turns in moving to adjacent vertices (or…

Computer Science and Game Theory · Computer Science 2013-11-15 R. Samal , T. Valla

We discuss winning possibilities of players in various variants of cops and robber game played on large random graphs, a testbed for various kinds of network queries, search problems in particular. We explore the use of logic frameworks to…

Logic in Computer Science · Computer Science 2025-12-01 Sourav Chakraborty , Sujata Ghosh , Smiha Samanta

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 the localization game played on graphs, wherein a set of cops attempt to determine the exact location of an invisible robber by exploiting distance probes. The corresponding optimization parameter for a graph $G$ is called the…

Combinatorics · Mathematics 2020-01-27 Anthony Bonato , William B. Kinnersley

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 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

We study versions of cop and robber pursuit-evasion games on the visibility graphs of polygons, and inside polygons with straight and curved sides. Each player has full information about the other player's location, players take turns, and…

Computational Geometry · Computer Science 2016-01-07 Anna Lubiw , Jack Snoeyink , Hamideh Vosoughpour

A gambler moves between the vertices $1, \ldots, n$ of a graph using the probability distribution $p_{1}, \ldots, p_{n}$. Multiple cops pursue the gambler on the graph, only being able to move between adjacent vertices. We investigate the…

Discrete Mathematics · Computer Science 2016-10-11 Jesse Geneson