Abstract
We present a proximal point type algorithm tailored for tackling pseudomonotone equilibrium problems in a Hilbert space which are not necessarily convex in the second argument of the involved bifunction. Motivated by the extragradient algorithm, we propose a two-step method and we prove that the generated sequence converges strongly to a solution of the nonconvex equilibrium problem under mild assumptions and, also, we establish a linear convergent rate for the iterates. Furthermore, we identify a new class of functions that meet our assumptions, and we provide sufficient conditions for quadratic fractional functions to exhibit strong quasiconvexity. Finally, we perform numerical experiments comparing our algorithm against two alternative methods for classes of nonconvex mixed variational inequalities.
Similar content being viewed by others
Data availability
No data sets were generated during the current study. The used python codes are available from all authors on reasonable request.
References
Attouch, H., Buttazzo, G., Michaille, G.: Variational Analysis in Sobolev and BV Spaces: Aplications to PDEs and Optimization. MPS-SIAM, Philadelphia (2006)
Baiocchi, C., Buttazzo, G., Gastaldi, F., Tomarelli, F.: General existence theorems for unilateral problems in continuum mechanics, Arch. J. Rational Mech. Anal. 100, 149–189 (1988)
Barton, E.N., Goebel, R., Jensen, R.R.: Functions which are quasiconvex under linear perturbations. SIAM J. Optim. 22, 1089–1105 (2012)
Bauschke, H.H., Combettes, P.L.: “Convex Analysis and Monotone Operators Theory in Hilbert Spaces”. CMS Books in Mathematics. Springer-Verlag, second edition, (2017)
Bigi, G., Castellani, M., Pappalardo, M., Passacantando, M.: Nonlinear Programming Techniques for Equilibria. Springer, Cham (2019)
Blum, E., Oettli, W.: From optimization and variational inequalities to equilibrium problems. Math. Student 63, 123–145 (1994)
Cambini, A., Martein, L.: “Generalized Convexity and Optimization: Theory and Applications”. Springer, (2009)
Debreu, G.: Theory of value. John Wiley, New York (1959)
Combettes, P.L., Hirstoaga, S.A.: Equilibrium programming in Hilbert spaces. J. Nonlinear Convex Anal. 6, 117–136 (2005)
Dong, N.T.P., Strodiot, J.J., Van, N.T.T., Nguyen, V.H.: A family of extragradient methods for solving equilibrium problems. J. Ind. Manag. Optim. 11, 619–630 (2015)
Facchinei, F., Pang, J.-S.: Finite-Dimensional Variational Inequalities and Complementarity Problems, vol. II. Springer, New York (2003)
Flores-Bazán, F.: Existence theorems for generalized noncoercive equilibrium problems: the quasi-convex case SIAM. J. Optim. 11, 675–690 (2000)
Frenk, J.B.G., Schaible, S.: Fractional programming. In: Hadjisavvas, N., et al. (eds.) Handbook of generalized convexity and generalized monotonicity", pp. 335–386. Springer, Boston (2005)
Grad, S.-M., Lara, F.: Solving mixed variational inequalities beyond convexity. J. Optim. Theory Appl. 190, 565–580 (2021)
Grad, S.-M., Lara, F., Marcavillaca, R.T.: Properties and proximal point type method for strongly quasiconvex functions in Hilbert spaces, Submitted, (2023)
Hadjisavvas, N., Komlosi, S., Schaible, S.: Handbook of Generalized Convexity and Generalized Monotonicity. Springer-Verlag, Boston (2005)
He, B.: Algorithm for a class of generalized linear variational inequality and its application. Sci China, A 25, 939–945 (1995)
He, B., He, X.-Z., Liu, H.K.: Solving a class of constrained “black-box” inverse variational inequalities. Eur. J. Oper. Res. 204, 391–401 (2010)
Iusem, A., Lara, F.: Second order asympotic functions and applications to quadratic programming. J. Convex Anal. 25(1), 271–291 (2018)
Iusem, A., Lara, F.: Optimality conditions for vector equilibrium problems with applications. J. Optim. Theory Appl. 180, 187–206 (2019)
Iusem, A., Lara, F.: Existence results for noncoercive mixed variational inequalities in finite dimensional spaces. J. Optim. Theory Appl. 183, 122–138 (2019)
Iusem, A., Lara, F.: Quasiconvex optimization and asymptotic analysis in Banach spaces. Optimization 69, 2453–2470 (2020)
Iusem, A., Lara, F.: A note on Existence results for noncoercive mixed variational inequalities in finite dimensional spaces’’. J. Optim. Theory Appl. 187, 607–608 (2020)
Iusem, A., Lara, F.: Proximal point algorithms for quasiconvex pseudomonotone equilibrium problems. J. Optim. Theory Appl. 193, 443–461 (2022)
Iusem, A., Kassay, G., Sosa, W.: On certain conditions for the existence of solutions of equilibrium problems. Math. Programm. 116, 259–273 (2009)
Jeyakumar, V., Oettli, W., Natividad, M.: A solvability theorem for a class of quasiconvex mappings with applications to optimization. J. Math. Anal. Appl. 179, 537–546 (1993)
Jovanović, M.: A note on strongly convex and quasiconvex functions. Math. Notes 60, 584–585 (1996)
Kabgani, A., Lara, F.: Strong subdifferentials: theory and applications in nonconvex optimization. J. Global Optim. 84, 349–368 (2022)
Kassay, G., Hai, T.N., Vinh, N.T.: Coupling Popov’s algorithm with subgradient extragradient method for solving equilibrium problems. J. Nonlinear Convex Anal. 19, 959–986 (2018)
Konnov, I.V.: Application of the proximal point method to nonmonotone equilibrium problems. J. Optim. Theory Appl. 119, 317–333 (2003)
Korpelevich, G.: The extragradient method for finding saddle points and other problems. Matecon 12, 747–756 (1976)
Fan, Ky.: A Minimax Inequality and Applications. In: Inequality, I.I.I. (ed.) Inquality, pp. 103–113. Academic Press, New York (1972)
Lara, F.: On strongly quasiconvex functions: existence results and proximal point algorithms. J. Optim. Theory Appl. 192, 891–911 (2022)
Lara, F.: On nonconvex pseudomonotone equilibrium problems with applications. Set-Valued Var. Anal. 30, 355–372 (2022)
Malitsky, Y.: Golden ratio algorithms for variational inequalities. Math. Programm. 184, 383–410 (2020)
Martinet, B.: Regularisation d’inequations variationelles par approximations successives. Rev. Francaise Inf. Rech. Oper. 4, 154–159 (1970)
Martinet, B.: Determination approcheed’un point fixed’une application pseudo-contractante, C.R. Acad. Sci. Paris 274, 163–165 (1972)
Mas-Colell, A., Whinston, M.D., Green, J.R.: Microeconomic Theory. Oxford University Press, Oxford (1995)
Mastroeni, G.: On auxiliary principle for equilibrium problems, Publ. Dip. Math. dell. Universita di Pisa 3, 1244–1258 (2000)
Moudafi, A., Théra, M.: Proximal and dynamical approaches to equilibrium problems. Springer, Berlin (1999)
Moudafi, A.: Viscosity approximation methods for fixed-point problems. J. Math. Anal. Appl. 241, 46–55 (2000)
Muu, L.D.: Stability property of a class of variational inequalities. Optimization 15, 347–351 (1984)
Ovcharova, N., Gwinner, J.: Semicoercive variational inequalities: From existence to numerical solutions of nonmonotone contact problems. J. Optim. Theory Appl. 171, 422–439 (2016)
Polyak, B.T.: Existence theorems and convergence of minimizing sequences in extremum problems with restrictions. Soviet Math. 7, 72–75 (1966)
Quoc, T.D., Muu, L.D., Hien, N.V.: Extragradient algorithms extended to equilibrium problems. Optimization 57, 749–766 (2008)
Rockafellar, R.T.: Monotone operators and proximal point algorithms. SIAM J. Control. Optim. 14, 877–898 (1976)
Rockafellar, R.T., Wets, R.: Generalized linear-quadratic problems of deterministic and stochastic optimal control in discrete time. SIAM J. Control. Optim. 28, 810–820 (1990)
Solodov, M.V., Svaiter, B.F.: A new projection method for variational inequality problems. SIAM J. Control. Optim. 37, 765–776 (1999)
Schaible, S.: Fractional programming. In: Horst, R., Pardalos, P. (eds.) Handbook of Global Optimization, pp. 495–608. Kluwer Academic Publishers, Dordrecht (1995)
Stancu-Minasian, I.M.: Fractional Programming: Theory, Methods and Applications. Kluwer Academic Publishers, London (1997)
Tran, D.Q., Dung, M.L., Nguyen, V.H.: Extragradient algorithms extended to equilibrium problems. Optimization 57, 749–776 (2008)
Takahashi, S., Takahashi, W.: Viscosity approximation methods for equilibrium problems and fixed point problems in Hilbert spaces. J. Math. Anal. Appl. 331, 4506–515 (2007)
Vladimirov, A.A., Nesterov, Ju.E., Chekanov, Ju.N.: O ravnomerno kvazivypuklyh funkcionalah On uniformly quasiconvex functionals, Vestn. Mosk. un-ta vycis. mat. i kibern. 4, 18–27 (1978)
von Neumann, J., Morgenstern, O.: Theory of Games and Economic Behavior. Princeton University Press, New Jersey (1944)
Vuong, P.T., Strodiot, J.J., Nguyen, V.H.: Extragradient methods and linesearch algorithms for solving Ky Fan inequalities and fixed point problems. J. Optim. Theory Appl. 155, 605–627 (2012)
Wang, M.: The existence results and Tikhonov regularization method for generalized mixed variational inequalities in Banach spaces. Ann. Math. Phys. 7, 151–163 (2017)
Yen, L.H., Muu, L.D.: An extragradient algorithm for quasiconvex equilibrium problems without monotonicity. J. Global Optim. (2023). https://doi.org/10.1007/s10898-023-01291-y
Zhao, Y.-B.: Iterative methods for monotone generalized variational inequalities. Optimization 42, 285–307 (1997)
Acknowledgements
Part of this work was carried out when F. Lara was visiting the Institute of Mathematics of the Vietnam Academy of Sciences and Technology (VAST), in Hanoi, Vietnam, during March 2023. This author wishes to thank the Institute for its hospitality.
Funding
This research was partially supported the MATH AmSud cooperation program Project AMSUD-220020 (Lara and Marcavillaca), by ANID–Chile under project Fondecyt Regular 1241040 (Lara), BASAL fund FB210005 for center of excellence from ANID-Chile (Marcavillaca) and by Vietnam Academy of Science and Technology under Grant Number CTTH00.02/24-25 (Yen).
Author information
Authors and Affiliations
Contributions
All authors contributed equally to the study conception, design and implementation, and wrote and corrected the manuscript.
Corresponding author
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
About this article
Cite this article
Iusem, A., Lara, F., Marcavillaca, R.T. et al. A Two-Step Proximal Point Algorithm for Nonconvex Equilibrium Problems with Applications to Fractional Programming. J Glob Optim 90, 755–779 (2024). https://doi.org/10.1007/s10898-024-01419-8
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10898-024-01419-8