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We investigate the complexity of bounding the uncertainty of graphical games, and we provide new insight into the intrinsic difficulty of computing Nash equilibria. In particular, we show that, if one adds very simple and natural additional…

Computer Science and Game Theory · Computer Science 2012-07-09 Gianluigi Greco , Francesco Scarcello

We consider polymatrix coordination games with individual preferences where every player corresponds to a node in a graph who plays with each neighbor a separate bimatrix game with non-negative symmetric payoffs. In this paper, we study…

Computer Science and Game Theory · Computer Science 2015-04-29 Mona Rahn , Guido Schäfer

We study the complexity of computing equilibria in binary public goods games on undirected graphs. In such a game, players correspond to vertices in a graph and face a binary choice of performing an action, or not. Each player's decision…

Computer Science and Game Theory · Computer Science 2023-05-22 Max Klimm , Maximilian J. Stahlberg

In recent work of Hazan and Krauthgamer (SICOMP 2011), it was shown that finding an $\eps$-approximate Nash equilibrium with near-optimal value in a two-player game is as hard as finding a hidden clique of size $O(\log n)$ in the random…

Computational Complexity · Computer Science 2011-04-20 Per Austrin , Mark Braverman , Eden Chlamtac

We study the problem of checking for the existence of constrained pure Nash equilibria in a subclass of polymatrix games defined on weighted directed graphs. The payoff of a player is defined as the sum of nonnegative rational weights on…

Computer Science and Game Theory · Computer Science 2016-11-30 Sunil Simon , Dominik Wojtczak

Whether a PTAS (polynomial-time approximation scheme) exists for game equilibria has been an open question, and its absence has indications and consequences in three fields: the practicality of methods in algorithmic game theory,…

Computer Science and Game Theory · Computer Science 2025-02-06 Hongbo Sun , Chongkun Xia , Junbo Tan , Bo Yuan , Xueqian Wang , Bin Liang

We know that the Nash equilibria of a game cannot be computed efficiently unless $P = PPAD$. But can they be learned? Are there dynamics that (1) can be computed efficiently by the players at each strategy profile and (2) are guaranteed to…

Computer Science and Game Theory · Computer Science 2026-04-17 Oliver Biggar , Christos Papadimitriou , Georgios Piliouras

In this paper, we study the dynamic behavior of Hedge, a well-known algorithm in theoretical machine learning and algorithmic game theory. The empirical average (arithmetic mean) of the iterates Hedge generates is known to converge to a…

Computer Science and Game Theory · Computer Science 2020-07-22 Ioannis Avramopoulos

We study the problem of computing approximate Nash equilibria (epsilon-Nash equilibria) in normal form games, where the number of players is a small constant. We consider the approach of looking for solutions with constant support size. It…

Computer Science and Game Theory · Computer Science 2008-12-18 Patrick Briest , Paul W. Goldberg , Heiko Roeglin

For a constant $\epsilon$, we prove a poly(N) lower bound on the (randomized) communication complexity of $\epsilon$-Nash equilibrium in two-player NxN games. For n-player binary-action games we prove an exp(n) lower bound for the…

Computer Science and Game Theory · Computer Science 2016-09-14 Yakov Babichenko , Aviad Rubinstein

We study the complexity of computing a uniform Nash equilibrium on a non-win-lose bimatrix game. It is known that such a problem is NP-complete even if a bimatrix game is win-lose (Bonifaci et al., 2008). Fortunately, if a win-lose bimatrix…

Computer Science and Game Theory · Computer Science 2022-08-23 Takashi Ishizuka , Naoyuki Kamiyama

We present a new methodology for computing approximate Nash equilibria for two-person non-cooperative games based upon certain extensions and specializations of an existing optimization approach previously used for the derivation of fixed…

Computer Science and Game Theory · Computer Science 2009-09-28 Haralampos Tsaknakis , Paul G. Spirakis

We revisit the complexity of deciding, given a {\it bimatrix game,} whether it has a {\it Nash equilibrium} with certain natural properties; such decision problems were early known to be ${\mathcal{NP}}$-hard~\cite{GZ89}. We show that…

Computational Complexity · Computer Science 2019-07-25 Vittorio Bilò , Marios Mavronicolas

Equilibria of realistic multiplayer games constitute a key solution concept both in practical applications, such as online advertising auctions and electricity markets, and in analytical frameworks used to study strategic voting in…

Computer Science and Game Theory · Computer Science 2025-11-18 Jakub Černý , Shuvomoy Das Gupta , Christian Kroer

This paper deals with the complexity of the problem of computing a pure Nash equilibrium for discrete preference games and network coordination games beyond $O(\log n)$-treewidth and tree metric spaces. First, we estimate the number of…

Computer Science and Game Theory · Computer Science 2022-07-05 Takashi Ishizuka , Naoyuki Kamiyama

A fundamental shortcoming of the concept of Nash equilibrium is its computational intractability: approximating Nash equilibria in normal-form games is PPAD-hard. In this paper, inspired by the ideas of smoothed analysis, we introduce a…

Computer Science and Game Theory · Computer Science 2024-07-23 Constantinos Daskalakis , Noah Golowich , Nika Haghtalab , Abhishek Shetty

Noncooperative game theory provides a normative framework for analyzing strategic interactions. However, for the toolbox to be operational, the solutions it defines will have to be computed. In this paper, we provide a single reduction that…

Computer Science and Game Theory · Computer Science 2007-05-23 Vincent Conitzer , Tuomas Sandholm

We study strategic games on weighted directed graphs, in which the payoff of a player is defined as the sum of the weights on the edges from players who chose the same strategy, augmented by a fixed non-negative integer bonus for picking a…

Computer Science and Game Theory · Computer Science 2021-03-15 Krzysztof R. Apt , Sunil Simon , Dominik Wojtczak

Strategic interactions can be represented more concisely, and analyzed and solved more efficiently, if we are aware of the symmetries within the multiagent system. Symmetries also have conceptual implications, for example for equilibrium…

Computer Science and Game Theory · Computer Science 2025-03-03 Emanuel Tewolde , Brian Hu Zhang , Caspar Oesterheld , Tuomas Sandholm , Vincent Conitzer

The Nash equilibrium is an important benchmark for behaviour in systems of strategic autonomous agents. Polymatrix games are a succinct and expressive representation of multiplayer games that model pairwise interactions between players. The…

Computer Science and Game Theory · Computer Science 2016-03-17 Argyrios Deligkas , John Fearnley , Tobenna Peter Igwe , Rahul Savani