Abstract
We attempt to provide an algorithm for approximating a solution of the quasiconvex equilibrium problem that was proved to exist by K. Fan 1972. The proposed algorithm is an iterative procedure, where the search direction at each iteration is a normal-subgradient, while the step-size is updated avoiding Lipschitz-type conditions. The algorithm is convergent to a \(\rho \)- quasi-solution with any positive \(\rho \) if the bifunction f is semistrictly quasiconvex in its second variable, while it converges to the solution when f is strongly quasiconvex. Neither monotoniciy nor Lipschitz property is required. The main subprogram needed to solve at each iteration is a proximal regularized minimization problem whose objective function is the sum of a quasiconvex function and the one \(\Vert .\Vert ^2\). We also discuss several cases where this global optimization problem can be solved efficiently.
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Acknowledgements
The authors would like to thank the anonymous reviewers for their constructive comments and suggestions which help us to improve the quality of the paper. The research of the second author was supported by the Vietnam Academy of Science and Technology under Grant Number CTTH00.01/22-23.
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Muu, L.D., Yen, L.H. An extragradient algorithm for quasiconvex equilibrium problems without monotonicity. J Glob Optim (2023). https://doi.org/10.1007/s10898-023-01291-y
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DOI: https://doi.org/10.1007/s10898-023-01291-y