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Avoidance games are games in which two players claim vertices of a hypergraph and try to avoid some structures. These games are studied since the introduction of the game of SIM in 1968, but only few complexity results are known on them. In…

Combinatorics · Mathematics 2022-10-07 Valentin Gledel , Nacim Oijid

Given $n$ piles of tokens and a positive integer $k \leq n$, the game Nim$^1_{n, =k}$ of exact slow $k$-Nim is played as follows. Two players move alternately. In each move, a player chooses exactly $k$ non-empty piles and removes one token…

Combinatorics · Mathematics 2021-02-09 Nikolay Chikin , Vladimir Gurvich , Konstantin Knop , Mike Paterson , Michael Vyalyi

This paper formalises the Canadian Traveller problem as a positional two-player game on graphs. We consider two variants depending on whether an edge is blocked. In the locally-informed variant, the traveller learns if an edge is blocked…

Data Structures and Algorithms · Computer Science 2024-07-24 Thomas Bellitto , Johanne Cohen , Bruno Escoffier , Minh-Hang Nguyen , Mikael Rabie

We consider two-player stochastic games played on a finite graph for infinitely many rounds. Stochastic games generalize both Markov decision processes (MDP) by adding an adversary player, and two-player deterministic games by adding…

Computer Science and Game Theory · Computer Science 2022-02-28 Laurent Doyen

Generalized Geography is a combinatorial game played on a directed graph. Players take turns moving a token from vertex to vertex, deleting a vertex after moving the token away from it. A player unable to move loses. It is well known that…

Computational Complexity · Computer Science 2021-08-24 Nathan Fox , Carson Geissler

We study a Stackelberg game to examine how two agents determine to cooperate while competing with each other. Each selects an arrival time to a destination, the earlier one fetching a higher reward. There is, however, an inherent penalty in…

Computer Science and Game Theory · Computer Science 2024-07-30 Chenlan Wang , Mehrdad Moharrami , Mingyan Liu

We study the maximum $k$-colorable subgraph (M$k$CS) problem, which consists in finding a largest $k$-colorable induced subgraph in a given graph. We consider a Semidefinite Programming (SDP) relaxation for the M$k$CS problem and regard its…

Optimization and Control · Mathematics 2026-05-05 Mathijs Barkel , Renata Sotirov

We define a two-player combinatorial game in which players take alternate turns; each turn consists on deleting a vertex of a graph, together with all the edges containing such vertex. If any vertex became isolated by a player's move then…

Combinatorics · Mathematics 2016-08-03 Richard Adams , Janae Dixon , Jennifer Elder , Jamie Peabody , Oscar Vega , Karen Willis

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

We study 2-player impartial games of the form take-away which produce P-positions (second player winning positions) corresponding to complementary Beatty sequences, given by the continued fractions (1;k,1,k,1,...) and (k+1;k,1,k,1,...). Our…

Combinatorics · Mathematics 2013-02-04 Urban Larsson , Mike Weimerskirch

We show that computing an equilibrium in atomic splittable congestion games with player-specific affine cost functions $l_{e,i}(x) = a_{e,i} x + b_{e,i}$ is $\mathsf{PPAD}$-complete. To prove that the problem is contained in…

Computer Science and Game Theory · Computer Science 2020-01-20 Max Klimm , Philipp Warode

Despite the many recent practical and theoretical breakthroughs in computational game theory, equilibrium finding in extensive-form team games remains a significant challenge. While NP-hard in the worst case, there are provably efficient…

Computer Science and Game Theory · Computer Science 2022-01-19 Brian Hu Zhang , Tuomas Sandholm

Kempe equivalence is a classical and important notion on vertex coloring in graph theory. In the present paper, we introduce several ideals associated with graphs and provide a method to determine whether two $k$-colorings are Kempe…

Combinatorics · Mathematics 2026-04-01 Hidefumi Ohsugi , Akiyoshi Tsuchiya

We analyze the computational complexity of Tetris clearing (determining whether the player can clear an initial board using a given sequence of pieces) and survival (determining whether the player can avoid losing before placing all the…

Computational Complexity · Computer Science 2026-03-11 MIT Hardness Group , Josh Brunner , Erik D. Demaine , Della Hendrickson , Jeffery Li

Each vertex of the infinite $2$-dimensional square lattice graph is assigned, independently, a label that reads trap with probability $p$, target with probability $q$, and open with probability $(1-p-q)$, and each edge is assigned,…

Probability · Mathematics 2025-12-18 Dhruv Bhasin , Sayar Karmakar , Moumanti Podder , Souvik Roy

Kill-all Go is a variant of Go in which Black tries to capture all white stones, while White tries to survive. We consider computational complexity of Kill-all Go with two rulesets, Chinese rules and Japanese rules. We prove that: (i)…

Computational Complexity · Computer Science 2019-11-27 Zhujun Zhang

We prove that Arithmetical Comprehension is equivalent to the determinacy of all clopen integer games in which each player has at most two moves per turn.

Logic · Mathematics 2025-10-15 Juan Pablo Aguilera , Thibaut Kouptchinsky

The Cops and Robber game is played on undirected finite graphs. $k$ cops and one robber are positioned on vertices and take turn in moving along edges. The cops win if, after a move, a cop and the robber are on the same vertex. A graph is…

Combinatorics · Mathematics 2011-11-10 Dirk Oliver Theis

We show that the Unconstrained Traveling Tournament Problem (UTTP) is APX-complete by presenting an L-reduction from a version of metric (1,2)-TSP to UTTP. Keywords: Traveling Tournament Problem, APX-complete, Approximation algorithms,…

Data Structures and Algorithms · Computer Science 2022-12-20 Salomon Bendayan , Joseph Cheriyan , Kevin K. H. Cheung

We propose a purely combinatorial quadratic time algorithm that for any $n$-vertex $P_{k}$-free tournament $T$, where $P_{k}$ is a directed path of length $k$, finds in $T$ a transitive subset of order $n^{\frac{c}{k\log(k)^{2}}}$. As a…

Combinatorics · Mathematics 2015-06-30 Krzysztof Choromanski