A convergent inexact solution method for equilibrium problems

We consider equilibrium problems with differentiable bifunctions. We adopt the well-known approach based on the reformulation of the equilibrium problem as a global optimization problem through an appropriate gap function. We propose a solution method based on the inexact (and hence, less expensive) evaluation of the gap function and on the employment of a nonmonotone line search. We prove global convergence properties of the proposed inexact method under standard assumptions. The resutls of numerical experiments are presented.