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Related papers: Hats: all or nothing

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The prisoners and hats puzzle, or simply the hat puzzle, is a family of games in which a group of prisoners are each assigned a colored hat and are asked to guess the color of their own hat. Various versions of the puzzle arise depending on…

Logic · Mathematics 2025-11-13 Souji Shizuma

We study the hat chromatic number of a graph defined in the following way: there is one player at each vertex of a loopless graph $G$, an adversary places a hat of one of $K$ colors on the head of each player, two players can see each…

Combinatorics · Mathematics 2019-05-13 Bartłomiej Bosek , Andrzej Dudek , Michał Farnik , Jarosław Grytczuk , Przemysław Mazur

A puzzle about prisoners trying to identify the color of a hat on their head leads to a version where there are k more hats than prisoners. This generalized puzzle is related to the independence number of the arrangement graph A(m, n) and…

Combinatorics · Mathematics 2019-03-25 Rob Pratt , Stan Wagon , Michael Wiener , Piotr Zielinski

Lionel Levine's hat challenge has $t$ players, each with a (very large, or infinite) stack of hats on their head, each hat independently colored at random black or white. The players are allowed to coordinate before the random colors are…

Combinatorics · Mathematics 2021-03-10 Ehud Friedgut , Gil Kalai , Guy Kindler

We study the hat guessing game on graphs. In this game, a player is placed on each vertex $v$ of a graph $G$ and assigned a colored hat from $h(v)$ possible colors. Each player makes a deterministic guess on their hat color based on the…

Combinatorics · Mathematics 2023-12-05 Jeremy Chizewer , I. M. J. McInnis , Mehrdad Sohrabi , Shriya Kaistha

Several different "hat games" have recently received a fair amount of attention. Typically, in a hat game, one or more players are required to correctly guess their hat colour when given some information about other players' hat colours.…

Combinatorics · Mathematics 2010-01-22 Maura B. Paterson , Douglas R. Stinson

Lionel Levine's hat challenge has $t$ players, each with a (very large, or infinite) stack of hats on their head, each hat independently colored at random black or white. The players are allowed to coordinate before the random colors are…

Combinatorics · Mathematics 2023-08-22 Noga Alon , Ehud Friedgut , Gil Kalai , Guy Kindler

We initiate the study of the hat guessing number of a graph where the adversary is only allowed to provide a proper coloring of the graph. This is the largest number $q$ for which there is a guessing strategy on each vertex that only…

In this note, we give an explicit polynomial-time executable strategy for Peter Winkler's hat guessing game that gives superior results if the distribution of hats is imbalanced. While Winkler's strategy guarantees in any case that $\lfloor…

Combinatorics · Mathematics 2013-03-29 Benjamin Doerr

We consider Lionel Levine's notorious hat puzzle with two players. Each player has a stack of hats on their head, and each hat is chosen independently to be either black or white. After observing only the other player's hats, players…

Probability · Mathematics 2025-03-13 Steven Heilman , Omer Tamuz

2023 undergraduate thesis on a deterministic "hat game." For a digraph $D$, each player stands on a vertex $v$, is assigned a hat from $h(v)$ possible colors, and makes $g(v)$ guesses of her hat's color based on her out-neighbors' hats. If…

Combinatorics · Mathematics 2025-07-30 I. M. J. McInnis

In a guessing game, players guess the value of a random real number selected using some probability density function. The winner may be determined in various ways; for example, a winner can be a player whose guess is closest in magnitude to…

Computer Science and Game Theory · Computer Science 2016-07-11 Anthony Mendes , Kent E. Morrison

In this paper we study the Three Hat Problem which appeared in Puzzle Corner of the Technology Review magazine. This puzzle gives a scenario in which three players wearing hats are sitting together and each hat can be seen by everyone…

History and Overview · Mathematics 2007-10-16 Brian Benson , Yang Wang

Two players alternate tossing a biased coin where the probability of getting heads is p. The current player is awarded alpha points for tails and alpha+beta for heads. The first player reaching n points wins. For a completely unfair coin…

Probability · Mathematics 2011-12-15 Robert W. Chen , Burton Rosenberg

We consider a two-player search game on a tree $T$. One vertex (unknown to the players) is randomly selected as the target. The players alternately guess vertices. If a guess $v$ is not the target, then both players are informed in which…

Probability · Mathematics 2022-02-07 Ravi B. Boppana , Joel Brewster Lewis

We start with the well-known game below: Two players hold a sheet of paper to their forehead on which a positive integer is written. The numbers are consecutive and each player can only see the number of the other one. In each time step,…

Combinatorics · Mathematics 2013-02-26 Felix Günther , Irina Mustata

We consider the following game, played on a $k$-uniform hypergraph $H$. There are $q$ colors available and two players take it in turns to color vertices. A partial coloring is proper if no edge is mono-chromatic. One player, A, wishes to…

Combinatorics · Mathematics 2019-02-11 Debsoumya Chakraborti , Alan Frieze , Mihir Hasabnis

We consider a matching problem, which is meaningful in team competitions, as well as in information theory, recommender systems, and assignment problems. In the competitions which we study, each competitor in a team order plays a match with…

Computer Science and Game Theory · Computer Science 2026-05-21 Haris Aziz , Jiarui Gan , Grzegorz Lisowski , Ali Pourmiri

In this paper we study a cooperative card game called Hanabi from the viewpoint of algorithmic combinatorial game theory. In Hanabi, each card has one among $c$ colors and a number between $1$ and $n$. The aim is to make, for each color, a…

Discrete Mathematics · Computer Science 2017-03-09 Jean-Francois Baffier , Man-Kwun Chiu , Yago Diez , Matias Korman , Valia Mitsou , André van Renssen , Marcel Roeloffzen , Yushi Uno

We consider a game with two players, consisting of a number of rounds, where the first player to win $n$ rounds becomes the overall winner. Who wins each individual round is governed by a certain urn having two types of balls (type 1 and…

Probability · Mathematics 2026-03-05 Stanislav Volkov , Magnus Wiktorsson