A Jacobi-type Newton method for Nash equilibrium problems with descent guarantees

Fuente: arXiv
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Auteurs principaux: Kolossoski, Oliver, Bueno, Luís Felipe, Haeser, Gabriel
Format: Preprint
Publié: 2022
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_version_ 1866912173301694464
author Kolossoski, Oliver
Bueno, Luís Felipe
Haeser, Gabriel
author_facet Kolossoski, Oliver
Bueno, Luís Felipe
Haeser, Gabriel
contents A common strategy for solving an unconstrained two-player Nash equilibrium problem with continuous variables is applying Newton's method to the system of nonlinear equations obtained by the corresponding first-order necessary optimality conditions. However, when taking into account the game dynamics, it is not clear what is the goal of each player when considering that they are taking their current decision following Newton's iterates. In this paper we provide an interpretation for Newton's iterate in view of the game dynamics as follows: instead of minimizing the quadratic approximation of their objective function parameterized by the other player current decision (as a typical Jacobi-type strategy), we show that the Newton iterate follows this approach but with the objective function parameterized by a prediction of the other player action, considering that they are following the same Newtonian strategy. This interpretation allows us to present a new Newtonian algorithm where a backtracking procedure is introduced in order to guarantee that the computed Newtonian directions, for each player, are descent directions for their corresponding parameterized functions. Thus, besides favoring global convergence, our algorithm also favors true minimizers instead of maximizers or saddle points, differently from the standard Newton method, which does not consider the minimization structure of the problem in the non-convex case. Thus, our method is more robust in comparison with other Jacobi-type strategies or the pure Newtonian approach, which is corroborated by our illustrative numerical experiments. We also present a proof of the well-definiteness of the algorithm under some standard assumptions, together with a thorough analysis of its convergence properties taking into account the game dynamics.
format Preprint
id arxiv_https___arxiv_org_abs_2209_11571
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle A Jacobi-type Newton method for Nash equilibrium problems with descent guarantees
Kolossoski, Oliver
Bueno, Luís Felipe
Haeser, Gabriel
Optimization and Control
49K99, 65K05, 90C30, 91A99
A common strategy for solving an unconstrained two-player Nash equilibrium problem with continuous variables is applying Newton's method to the system of nonlinear equations obtained by the corresponding first-order necessary optimality conditions. However, when taking into account the game dynamics, it is not clear what is the goal of each player when considering that they are taking their current decision following Newton's iterates. In this paper we provide an interpretation for Newton's iterate in view of the game dynamics as follows: instead of minimizing the quadratic approximation of their objective function parameterized by the other player current decision (as a typical Jacobi-type strategy), we show that the Newton iterate follows this approach but with the objective function parameterized by a prediction of the other player action, considering that they are following the same Newtonian strategy. This interpretation allows us to present a new Newtonian algorithm where a backtracking procedure is introduced in order to guarantee that the computed Newtonian directions, for each player, are descent directions for their corresponding parameterized functions. Thus, besides favoring global convergence, our algorithm also favors true minimizers instead of maximizers or saddle points, differently from the standard Newton method, which does not consider the minimization structure of the problem in the non-convex case. Thus, our method is more robust in comparison with other Jacobi-type strategies or the pure Newtonian approach, which is corroborated by our illustrative numerical experiments. We also present a proof of the well-definiteness of the algorithm under some standard assumptions, together with a thorough analysis of its convergence properties taking into account the game dynamics.
title A Jacobi-type Newton method for Nash equilibrium problems with descent guarantees
topic Optimization and Control
49K99, 65K05, 90C30, 91A99
url https://arxiv.org/abs/2209.11571