5 research outputs found
Learning quadratic games on networks
Individuals, or organizations, cooperate with or compete against one another in a wide range of practical situations. Such strategic interactions are often modeled as games played on networks, where an individual’s payoff depends not only on her action but also on that of her neighbors. The current literature has largely focused on analyzing the characteristics of network games in the scenario where the structure of the network, which is represented by a graph, is known beforehand. It is often the case, however, that the actions of the players are readily observable while the underlying interaction network remains hidden. In this paper, we propose two novel frameworks for learning, from the observations on individual actions, network games with linear-quadratic payoffs, and in particular, the structure of the interaction network. Our frameworks are based on the Nash equilibrium of such games and involve solving a joint optimization problem for the graph structure and the individual marginal benefits. Both synthetic and real-world experiments demonstrate the effectiveness of the proposed frameworks, which have theoretical as well as practical implications for understanding strategic interactions in a network environment
Distributed Online Convex Optimization with an Aggregative Variable
This paper investigates distributed online convex optimization in the
presence of an aggregative variable without any global/central coordinators
over a multi-agent network, where each individual agent is only able to access
partial information of time-varying global loss functions, thus requiring local
information exchanges between neighboring agents. Motivated by many
applications in reality, the considered local loss functions depend not only on
their own decision variables, but also on an aggregative variable, such as the
average of all decision variables. To handle this problem, an Online
Distributed Gradient Tracking algorithm (O-DGT) is proposed with exact gradient
information and it is shown that the dynamic regret is upper bounded by three
terms: a sublinear term, a path variation term, and a gradient variation term.
Meanwhile, the O-DGT algorithm is also analyzed with stochastic/noisy
gradients, showing that the expected dynamic regret has the same upper bound as
the exact gradient case. To our best knowledge, this paper is the first to
study online convex optimization in the presence of an aggregative variable,
which enjoys new characteristics in comparison with the conventional scenario
without the aggregative variable. Finally, a numerical experiment is provided
to corroborate the obtained theoretical results
Learning to infer structures of network games
Strategic interactions between a group of individuals or organisations can be modelled as games played on networks, where a player’s payoff depends not only on their actions but also on those of their neighbours. Inferring the network structure from observed game outcomes (equilibrium actions) is an important problem with numerous potential applications in economics and social sciences. Existing methods mostly require the knowledge of the utility function associated with the game, which is often unrealistic to obtain in real-world scenarios. We adopt a transformer-like architecture which correctly accounts for the symmetries of the problem and learns a mapping from the equilibrium actions to the network structure of the game without explicit knowledge of the utility function. We test our method on three different types of network games using both synthetic and real-world data, and demonstrate its effectiveness in network structure inference and superior performance over existing methods
Local aggregative games
© 2017 Neural information processing systems foundation. All rights reserved. Aggregative games provide a rich abstraction to model strategic multi-agent interactions. We introduce local aggregative games, where the payoff of each player is a function of its own action and the aggregate behavior of its neighbors in a connected digraph. We show the existence of a pure strategy e-Nash equilibrium in such games when the payoff functions are convex or sub-modular. We prove an information theoretic lower bound, in a value oracle model, on approximating the structure of the digraph with non-negative monotone sub-modular cost functions on the edge set cardinality. We also define a new notion of structural stability, and introduce 7-aggregative games that generalize local aggregative games and admit e-Nash equilibrium that is stable with respect to small changes in some specified graph property. Moreover, we provide algorithms for our models that can meaningfully estimate the game structure and the parameters of the aggregator function from real voting data