Narrow Results

This paper is concerned with the application of Stackelberg–Nash strategies to control fourth-order linear and semilinear parabolic equations. We assume that the system is acted through a hierarchy of distributed controls: one main control (the leader) that is responsible for an exact controllability property; and a couple of secondary controls (the followers) that minimize two prescribed cost functionals and provide a pair of Nash equilibria for the two prescribed cost functionals. We first prove the existence of an associated Nash equilibrium pair corresponding to a hierarchical bi-objective optimal control problem for each leader by Lax–Milgram theorem. Then, we establish observability inequalities of fourth-order coupled parabolic equations by global Carleman inequalities and energy methods. Based on these results, we obtain the existence of a leader that drives the controlled system exactly to a prescribed (but arbitrary) trajectory. Furthermore, we also give the second-order sufficient conditions of optimality for the secondary controls.

This paper studies two pursuit-evasion problems under distance conditions in frame of differential game. In particular, a zero-sum differential game with the objective of distance and a nonzero-sum differential game with objective of both distance and azimuth adjustment are presented. The two players in the games are described by a nonlinear dynamics model subject to both speed and acceleration constraints in the two-dimensional plane. Instead of numerical solutions, the explicit equilibrium solutions of these two differential games are given under the condition that the distance between two players is larger than a certain value. Finally, the simulation results of these two differential games under typical cases demonstrate the effectiveness of our method.

In this paper we present applications of polynomial algebra for the problem of computing Nash equilibria of a subclass of finite normal form games.We characterize Nash equilibria of a normal form game as solutions to a system of polynomial equations and define the subclass of games under consideration. We present an algebraic method for deciding membership decision to the subclass of games. A method based on group action to compute all Nash equilibria of the subclass of games is presented with examples to show working of the methods. We also present some related results and discuss properties of the subclass of games.

We focus on the problem of learning equilibria in a particular routing game similar to the Wardrop traffic model. We describe a routing game played by a large number of players and present a distributed learning algorithm that we prove to converge weakly to equilibria for the system. The proof of convergence is based on a differential equation governing the global evolution of the system that is inferred from all the local evolutions of the agents in play. We prove that the differential equation converges with the help of Lyapunov techniques.

We determine the complexity of computing pure Nash equilibria in restricted network congestion games. Restricted network congestion games are network congestion games, where for each player there exits a set of edges which he is not allowed to use. Rosenthal's potential function guarantees the existence of a Nash Equilibrium. We show that computing a Nash equilibrium in a restricted network congestion game with two players is -complete, using a tight reduction from MAXCUT. The result holds for directed networks and for undirected networks.

A nonlinear four oligopolies price game with heterogeneous players, that are boundedly rational and adaptive, is built using two different special demand costs. Based on the theory of complex discrete dynamical system, the stability and the existing equilibrium point are investigated. The complex dynamic behavior is presented via bifurcation diagrams, the Lyapunov exponents to show equilibrium state, bifurcation and chaos with the variation in parameters. As disturbance is ubiquitous in economic systems, this paper focuses on the analysis of delay feedback control method under noise circumstances. Stable dynamics is confirmed to depend mainly on the low price adjustment speed, and if all four players have limited opportunities to stabilize the market, the new adaptive player facing profits of scale are found to be higher than the incumbents of bounded rational.

In this paper we investigate the set of correlated equilibria of bimatrix games. These equilibria are interesting, because they can result in outcome profiles that are not feasible as a result of Nash equilibria. After giving an example to illustrate the various concepts, we present a Projection Theorem which relates the two types of equilibria. Some lemmas are provided to clarify and extend this theorem.

A technique is proposed to represent games in characteristic function form as games in normal form, enabling the former to exploit the concepts of solution of the latter. A new solution for games in characteristic function form is then introduced and some properties are found. A generalization of a result of von Neumann and Morgenstern is thus obtained.

We develop an interactive model involving competitive tax evasion to determine optimal transfer prices by multinational firms. We establish that the proposed game is characterized by multiple equilibria. Implications of these multiple equilibria are examined.

Consider G = (X₁,…,X_M,g₁,…,g_M) an M-player game in strategic form, where the set X_i is an interval of real numbers and the payoff functions g_i are differentiable with respect to the related variable x_i ∈ X_i. If they are also concave, with respect to the related variable, then it is possible to associate to the game G a variational inequality which characterizes its Nash equilibrium points. In this paper it is considered the variational inequality for two sets of Cournot oligopoly games. In the first case, for any i = 1,…,M, we have X_i = [0,+∞); the market price function is in C¹ and convex; the cost production function of the player i is linear and the function x_i → g_i(…,x_i,…) is strictly concave. We prove the existence and uniqueness of the Nash equilibrium point and illustrate, with an example, an algorithm which calculates its components. In the second case, for any i = 1,…,M, we have X_i = [0,+∞); the market price function is in C² and concave and the cost production function of the i-player is in C² and convex. In these circumstances, as a consequence of well known facts, the existence and uniqueness of the Nash equilibrium point are guaranteed and also the Tykhonov and Hadamard well-posedness of the game. We prove that the game G is well posed with respect to its variational inequality.

In this study we provide a more robust transboundary industrial pollution reduction strategy for global emission collaborations. We consider the dynamics of each country’s quantity of pollution as a Brownian motion with Jumps to capture the systematic jumps caused by surprise effects arising from policy uncertainties within the economy. When the output of each country’s domestic consumption good production is proportional to the level of pollution emissions, we apply optimal control theory to find the Nash noncooperative, cooperative and Stackelberg optimal emission paths. To formulate this problem we allow each country’s discounted stream of net revenues to be maximized via a Stochastic Differential Game (SDG). We then articulate the Nash noncooperative equilibria, cooperative equilibria and Stackelberg equilibria via a feedback control strategy. We show that the outcome of the game depends on the parameters of the game and the type of equilibrium one considers. Furthermore, in this continuous-time differential game paradigm model we show that the feedback Stackelberg equilibrium will not coincide with the feedback Nash noncooperative equilibrium. In this setting, if the first mover advantage of the leader (Player I) disappears then both equilibria coincide.

In this paper, a class of generalized convex games is introduced. Existence properties of Nash equilibria, in mixed and pure strategies, are proposed. These properties are studied by considering limit cases related to a specific class of semi-lattice games. We propose an interpretation of our results based on Atkinson’s notion of generalized means. We also show that our approach makes it possible to propose a preference scheme taking into account the notion of prioritarianism.

We present some exact controllability results for parabolic equations in the context of hierarchic control using Stackelberg–Nash strategies. We analyze two cases: in the first one, the main control (the leader) acts in the interior of the domain and the secondary controls (the followers) act on small parts of the boundary; in the second one, we consider a leader acting on the boundary while the followers are of the distributed kind. In both cases, for each leader, an associated Nash equilibrium pair is found; then, we obtain a leader that leads the system exactly to a prescribed (but arbitrary) trajectory. We consider linear and semilinear problems.

We present a model for evacuees' exit selection in emergency evacuations. The model is based on the game theoretic concept of best-response dynamics, where each player updates his strategy periodically by reacting optimally to other players' strategies. A fixed point of the system of all players' best-response functions defines a Nash equilibrium (NE) of the game. In the model, the players are the evacuees and the strategies are the possible target exits. We present a mathematical formulation for the model and show that the game has a NE with pure strategies. We also analyze different iterative methods for finding the NE and derive an upper bound for the number of iterations needed to find the equilibrium. Numerical simulations are used to analyze the properties of the model.

We develop an octonionic representation of the payoff function for three player, two strategy, maximally entangled quantum games in order to obtain computationally friendly version of this function. This computational capability is then exploited to analyze and potentially classify the Nash equilibria in the quantum games.

Landsburg method of classifying mixed Nash equilibria for maximally entangled Eisert–Lewenstein–Wilkens (ELW) game is analyzed with special emphasis on symmetries inherent to the problem. Nash equilibria for the original ELW game are determined.

The explicit construction is presented of two-player game satisfying: (i) symmetry with respect to the permutation of the players; (ii) the existence of upper bound on total payoff following from Bell inequality; (iii) the existence of unfair equilibrium with total payoff saturating the above bound. The quantum counterpart of the game is considered which possesses only fair equilibria and strategies outperforming the classical ones.